Commit e573e978fb12 ("perf cs-etm: Inject capabilitity for CoreSight traces") reworks the samples generation flow from CoreSight trace to match the correct format so Perf report tool can display the samples properly.

But the change has side effect for branch packet handling, it only generate branch samples by checking previous packet flag 'last_instr_taken_branch' is true, this results in below three kinds packets are missed to generate branch samples:

- The start tracing packet at the beginning of tracing data; - The exception handling packet; - If one CS_ETM_TRACE_ON packet is inserted, we also miss to handle it for branch samples. CS_ETM_TRACE_ON packet itself can give the info that there have a discontinuity in the trace, on the other hand we also miss to generate proper branch sample for packets before and after CS_ETM_TRACE_ON packet.

This patch is to add branch sample handling for up three kinds packets:

- In function cs_etm__sample(), check if 'prev_packet->sample_type' is zero and in this case it generates branch sample for the start tracing packet; furthermore, we also need to handle the condition for prev_packet::end_addr is zero in the cs_etm__last_executed_instr();

- In function cs_etm__sample(), check if 'prev_packet->exc' is true and generate branch sample for exception handling packet;

- If there has one CS_ETM_TRACE_ON packet is coming, we firstly generate branch sample in the function cs_etm__flush(), this can save complete info for the previous CS_ETM_RANGE packet just before CS_ETM_TRACE_ON packet. We also generate branch sample for the new CS_ETM_RANGE packet after CS_ETM_TRACE_ON packet, this have two purposes, the first one purpose is to save the info for the new CS_ETM_RANGE packet, the second purpose is to save CS_ETM_TRACE_ON packet info so we can have hint for a discontinuity in the trace.

For CS_ETM_TRACE_ON packet, its fields 'packet->start_addr' and 'packet->end_addr' equal to 0xdeadbeefdeadbeefUL which are emitted in the decoder layer as dummy value. This patch is to convert these values to zeros for more readable; this is accomplished by functions cs_etm__last_executed_instr() and cs_etm__first_executed_instr(). The later one is a new function introduced by this patch.

Reviewed-by: Robert Walker robert.walker@arm.com Fixes: e573e978fb12 ("perf cs-etm: Inject capabilitity for CoreSight traces") Signed-off-by: Leo Yan leo.yan@linaro.org --- tools/perf/util/cs-etm.c | 93 +++++++++++++++++++++++++++++++++++++----------- 1 file changed, 73 insertions(+), 20 deletions(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 822ba91..8418173 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -495,6 +495,20 @@ static inline void cs_etm__reset_last_branch_rb(struct cs_etm_queue *etmq) static inline u64 cs_etm__last_executed_instr(struct cs_etm_packet *packet) { /* + * The packet is the start tracing packet if the end_addr is zero, + * returns 0 for this case. + */ + if (!packet->end_addr) + return 0; + + /* + * The packet is the CS_ETM_TRACE_ON packet if the end_addr is + * magic number 0xdeadbeefdeadbeefUL, returns 0 for this case. + */ + if (packet->end_addr == 0xdeadbeefdeadbeefUL) + return 0; + + /* * The packet records the execution range with an exclusive end address * * A64 instructions are constant size, so the last executed @@ -505,6 +519,18 @@ static inline u64 cs_etm__last_executed_instr(struct cs_etm_packet *packet) return packet->end_addr - A64_INSTR_SIZE; }

+static inline u64 cs_etm__first_executed_instr(struct cs_etm_packet *packet) +{ + /* + * The packet is the CS_ETM_TRACE_ON packet if the start_addr is + * magic number 0xdeadbeefdeadbeefUL, returns 0 for this case. + */ + if (packet->start_addr == 0xdeadbeefdeadbeefUL) + return 0; + + return packet->start_addr; +} + static inline u64 cs_etm__instr_count(const struct cs_etm_packet *packet) { /* @@ -546,7 +572,7 @@ static void cs_etm__update_last_branch_rb(struct cs_etm_queue *etmq)

be = &bs->entries[etmq->last_branch_pos]; be->from = cs_etm__last_executed_instr(etmq->prev_packet); - be->to = etmq->packet->start_addr; + be->to = cs_etm__first_executed_instr(etmq->packet); /* No support for mispredict */ be->flags.mispred = 0; be->flags.predicted = 1; @@ -701,7 +727,7 @@ static int cs_etm__synth_branch_sample(struct cs_etm_queue *etmq) sample.ip = cs_etm__last_executed_instr(etmq->prev_packet); sample.pid = etmq->pid; sample.tid = etmq->tid; - sample.addr = etmq->packet->start_addr; + sample.addr = cs_etm__first_executed_instr(etmq->packet); sample.id = etmq->etm->branches_id; sample.stream_id = etmq->etm->branches_id; sample.period = 1; @@ -897,13 +923,28 @@ static int cs_etm__sample(struct cs_etm_queue *etmq) etmq->period_instructions = instrs_over; }

- if (etm->sample_branches && - etmq->prev_packet && - etmq->prev_packet->sample_type == CS_ETM_RANGE && - etmq->prev_packet->last_instr_taken_branch) { - ret = cs_etm__synth_branch_sample(etmq); - if (ret) - return ret; + if (etm->sample_branches && etmq->prev_packet) { + bool generate_sample = false; + + /* Generate sample for start tracing packet */ + if (etmq->prev_packet->sample_type == 0 || + etmq->prev_packet->sample_type == CS_ETM_TRACE_ON) + generate_sample = true; + + /* Generate sample for exception packet */ + if (etmq->prev_packet->exc == true) + generate_sample = true; + + /* Generate sample for normal branch packet */ + if (etmq->prev_packet->sample_type == CS_ETM_RANGE && + etmq->prev_packet->last_instr_taken_branch) + generate_sample = true; + + if (generate_sample) { + ret = cs_etm__synth_branch_sample(etmq); + if (ret) + return ret; + } }

if (etm->sample_branches || etm->synth_opts.last_branch) { @@ -922,11 +963,16 @@ static int cs_etm__sample(struct cs_etm_queue *etmq) static int cs_etm__flush(struct cs_etm_queue *etmq) { int err = 0; + struct cs_etm_auxtrace *etm = etmq->etm; struct cs_etm_packet *tmp;

- if (etmq->etm->synth_opts.last_branch && - etmq->prev_packet && - etmq->prev_packet->sample_type == CS_ETM_RANGE) { + if (!etmq->prev_packet) + return 0; + + if (etmq->prev_packet->sample_type != CS_ETM_RANGE) + return 0; + + if (etmq->etm->synth_opts.last_branch) { /* * Generate a last branch event for the branches left in the * circular buffer at the end of the trace. @@ -939,18 +985,25 @@ static int cs_etm__flush(struct cs_etm_queue *etmq) err = cs_etm__synth_instruction_sample( etmq, addr, etmq->period_instructions); + if (err) + return err; etmq->period_instructions = 0; + }

- /* - * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for - * the next incoming packet. - */ - tmp = etmq->packet; - etmq->packet = etmq->prev_packet; - etmq->prev_packet = tmp; + if (etm->sample_branches) { + err = cs_etm__synth_branch_sample(etmq); + if (err) + return err; }

- return err; + /* + * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for + * the next incoming packet. + */ + tmp = etmq->packet; + etmq->packet = etmq->prev_packet; + etmq->prev_packet = tmp; + return 0; }

static int cs_etm__run_decoder(struct cs_etm_queue *etmq)

This commit adds python script to parse CoreSight tracing event and use command 'objdump' for disassembled lines, finally we can generate readable program execution flow for reviewing tracing data.

The script receives CoreSight tracing packet with below format:

+------------+------------+------------+ packet(n): | addr | ip | cpu | +------------+------------+------------+ packet(n+1): | addr | ip | cpu | +------------+------------+------------+

packet::ip is the last address of current branch instruction and packet::addr presents the start address of the next coming branch instruction. So for one branch instruction which starts in packet(n), its execution flow starts from packet(n)::addr and it stops at packet(n+1)::ip. As results we need to combine the two continuous packets to generate the instruction range, this is the rationale for the script implementation:

[ sample(n)::addr .. sample(n+1)::ip ]

Credits to Tor Jeremiassen who have written the script skeleton and provides the ideas for reading symbol file according to build-id, creating memory map for dso and basic packet handling. Mathieu Poirier contributed fixes for build-id and memory map bugs. The detailed development history for this script you can find from [1]. Based on Tor and Mathieu work, the script is updated samples handling for the corrected sample format. Another minor enhancement is to support for without build-id case, the script can parse kernel symbols with option '-k' for vmlinux file path.

[1] https://github.com/Linaro/perf-opencsd/commits/perf-opencsd-v4.15/tools/perf...

Co-authored-by: Tor Jeremiassen tor@ti.com Co-authored-by: Mathieu Poirier mathieu.poirier@linaro.org Signed-off-by: Leo Yan leo.yan@linaro.org --- tools/perf/scripts/python/arm-cs-trace-disasm.py | 235 +++++++++++++++++++++++ 1 file changed, 235 insertions(+) create mode 100644 tools/perf/scripts/python/arm-cs-trace-disasm.py

diff --git a/tools/perf/scripts/python/arm-cs-trace-disasm.py b/tools/perf/scripts/python/arm-cs-trace-disasm.py new file mode 100644 index 0000000..1239ab4 --- /dev/null +++ b/tools/perf/scripts/python/arm-cs-trace-disasm.py @@ -0,0 +1,235 @@ +# arm-cs-trace-disasm.py: ARM CoreSight Trace Dump With Disassember +# SPDX-License-Identifier: GPL-2.0 +# +# Tor Jeremiassen tor@ti.com is original author who wrote script +# skeleton, Mathieu Poirier mathieu.poirier@linaro.org contributed +# fixes for build-id and memory map; Leo Yan leo.yan@linaro.org +# updated the packet parsing with new samples format. + +import os +import sys +import re +from subprocess import * +from optparse import OptionParser, make_option + +# Command line parsing + +option_list = [ + # formatting options for the bottom entry of the stack + make_option("-k", "--vmlinux", dest="vmlinux_name", + help="Set path to vmlinux file"), + make_option("-d", "--objdump", dest="objdump_name", + help="Set path to objdump executable file"), + make_option("-v", "--verbose", dest="verbose", + action="store_true", default=False, + help="Enable debugging log") +] + +parser = OptionParser(option_list=option_list) +(options, args) = parser.parse_args() + +if (options.objdump_name == None): + sys.exit("No objdump executable file specified - use -d or --objdump option") + +# Initialize global dicts and regular expression + +build_ids = dict() +mmaps = dict() +disasm_cache = dict() +cpu_data = dict() +disasm_re = re.compile("^\s*([0-9a-fA-F]+):") +disasm_func_re = re.compile("^\s*([0-9a-fA-F]+)\s<.*>:") +cache_size = 32*1024 +prev_cpu = -1 + +def parse_buildid(): + global build_ids + + buildid_regex = "([a-fA-f0-9]+)[ \t]([^ \n]+)" + buildid_re = re.compile(buildid_regex) + + results = check_output(["perf", "buildid-list"]).split('\n'); + for line in results: + m = buildid_re.search(line) + if (m == None): + continue; + + id_name = m.group(2) + id_num = m.group(1) + + if (id_name == "[kernel.kallsyms]") : + append = "/kallsyms" + elif (id_name == "[vdso]") : + append = "/vdso" + else: + append = "/elf" + + build_ids[id_name] = os.environ['PERF_BUILDID_DIR'] + \ + "/" + id_name + "/" + id_num + append; + # Replace duplicate slash chars to single slash char + build_ids[id_name] = build_ids[id_name].replace('//', '/', 1) + + if ((options.vmlinux_name == None) and ("[kernel.kallsyms]" in build_ids)): + print "kallsyms cannot be used to dump assembler" + + # Set vmlinux path to replace kallsyms file, if without buildid we still + # can use vmlinux to prase kernel symbols + if ((options.vmlinux_name != None)): + build_ids['[kernel.kallsyms]'] = options.vmlinux_name; + +def parse_mmap(): + global mmaps + + # Check mmap for PERF_RECORD_MMAP and PERF_RECORD_MMAP2 + mmap_regex = "PERF_RECORD_MMAP.* -?[0-9]+/[0-9]+: [(0x[0-9a-fA-F]+)((0x[0-9a-fA-F]+)).*:\s.*\s(\S*)" + mmap_re = re.compile(mmap_regex) + + results = check_output("perf script --show-mmap-events | fgrep PERF_RECORD_MMAP", shell=True).split('\n') + for line in results: + m = mmap_re.search(line) + if (m != None): + if (m.group(3) == '[kernel.kallsyms]_text'): + dso = '[kernel.kallsyms]' + else: + dso = m.group(3) + + start = int(m.group(1),0) + end = int(m.group(1),0) + int(m.group(2),0) + mmaps[dso] = [start, end] + +def find_dso_mmap(addr): + global mmaps + + for key, value in mmaps.items(): + if (addr >= value[0] and addr < value[1]): + return key + + return None + +def read_disam(dso, start_addr, stop_addr): + global mmaps + global build_ids + + addr_range = start_addr + ":" + stop_addr; + + # Don't let the cache get too big, clear it when it hits max size + if (len(disasm_cache) > cache_size): + disasm_cache.clear(); + + try: + disasm_output = disasm_cache[addr_range]; + except: + try: + fname = build_ids[dso]; + except KeyError: + sys.exit("cannot find symbol file for " + dso) + + disasm = [ options.objdump_name, "-d", "-z", + "--start-address="+start_addr, + "--stop-address="+stop_addr, fname ] + + disasm_output = check_output(disasm).split('\n') + disasm_cache[addr_range] = disasm_output; + + return disasm_output + +def dump_disam(dso, start_addr, stop_addr): + for line in read_disam(dso, start_addr, stop_addr): + m = disasm_func_re.search(line) + if (m != None): + print "\t",line + continue + + m = disasm_re.search(line) + if (m == None): + continue; + + print "\t",line + +def dump_packet(sample): + print "Packet = { cpu: 0x%d addr: 0x%x phys_addr: 0x%x ip: 0x%x " \ + "pid: %d tid: %d period: %d time: %d }" % \ + (sample['cpu'], sample['addr'], sample['phys_addr'], \ + sample['ip'], sample['pid'], sample['tid'], \ + sample['period'], sample['time']) + +def trace_begin(): + print 'ARM CoreSight Trace Data Assembler Dump' + parse_buildid() + parse_mmap() + +def trace_end(): + print 'End' + +def trace_unhandled(event_name, context, event_fields_dict): + print ' '.join(['%s=%s'%(k,str(v))for k,v in sorted(event_fields_dict.items())]) + +def process_event(param_dict): + global cache_size + global options + global prev_cpu + + sample = param_dict["sample"] + + if (options.verbose == True): + dump_packet(sample) + + # If period doesn't equal to 1, this packet is for instruction sample + # packet, we need drop this synthetic packet. + if (sample['period'] != 1): + print "Skip synthetic instruction sample" + return + + cpu = format(sample['cpu'], "d"); + + # Initialize CPU data if it's empty, and directly return back + # if this is the first tracing event for this CPU. + if (cpu_data.get(str(cpu) + 'addr') == None): + cpu_data[str(cpu) + 'addr'] = format(sample['addr'], "#x") + prev_cpu = cpu + return + + # The format for packet is: + # + # +------------+------------+------------+ + # sample_prev: | addr | ip | cpu | + # +------------+------------+------------+ + # sample_next: | addr | ip | cpu | + # +------------+------------+------------+ + # + # We need to combine the two continuous packets to get the instruction + # range for sample_prev::cpu: + # + # [ sample_prev::addr .. sample_next::ip ] + # + # For this purose, sample_prev::addr is stored into cpu_data structure + # and read back for 'start_addr' when the new packet comes, and we need + # to use sample_next::ip to calculate 'stop_addr', plusing extra 4 for + # 'stop_addr' is for the sake of objdump so the final assembler dump can + # include last instruction for sample_next::ip. + + start_addr = cpu_data[str(prev_cpu) + 'addr'] + stop_addr = format(sample['ip'] + 4, "#x") + + # Record for previous sample packet + cpu_data[str(cpu) + 'addr'] = format(sample['addr'], "#x") + prev_cpu = cpu + + # Handle CS_ETM_TRACE_ON packet if start_addr=0 and stop_addr=4 + if (int(start_addr, 0) == 0 and int(stop_addr, 0) == 4): + print "CPU%s: CS_ETM_TRACE_ON packet is inserted" % cpu + return + + # Sanity checking dso for start_addr and stop_addr + prev_dso = find_dso_mmap(int(start_addr, 0)) + next_dso = find_dso_mmap(int(stop_addr, 0)) + + # If cannot find dso so cannot dump assembler, bail out + if (prev_dso == None or next_dso == None): + print "Address range [ %s .. %s ]: failed to find dso" % (start_addr, stop_addr) + return + elif (prev_dso != next_dso): + print "Address range [ %s .. %s ]: isn't in same dso" % (start_addr, stop_addr) + return + + dump_disam(prev_dso, start_addr, stop_addr)

Leo and/or Robert,

On Mon, May 28, 2018 at 04:45:00PM +0800, Leo Yan wrote:

Commit e573e978fb12 ("perf cs-etm: Inject capabilitity for CoreSight traces") reworks the samples generation flow from CoreSight trace to match the correct format so Perf report tool can display the samples properly.

But the change has side effect for branch packet handling, it only generate branch samples by checking previous packet flag 'last_instr_taken_branch' is true, this results in below three kinds packets are missed to generate branch samples:

• The start tracing packet at the beginning of tracing data;
• The exception handling packet;
• If one CS_ETM_TRACE_ON packet is inserted, we also miss to handle it for branch samples. CS_ETM_TRACE_ON packet itself can give the info that there have a discontinuity in the trace, on the other hand we also miss to generate proper branch sample for packets before and after CS_ETM_TRACE_ON packet.

This patch is to add branch sample handling for up three kinds packets:

• In function cs_etm__sample(), check if 'prev_packet->sample_type' is zero and in this case it generates branch sample for the start tracing packet; furthermore, we also need to handle the condition for prev_packet::end_addr is zero in the cs_etm__last_executed_instr();

• In function cs_etm__sample(), check if 'prev_packet->exc' is true and generate branch sample for exception handling packet;

• If there has one CS_ETM_TRACE_ON packet is coming, we firstly generate branch sample in the function cs_etm__flush(), this can save complete info for the previous CS_ETM_RANGE packet just before CS_ETM_TRACE_ON packet. We also generate branch sample for the new CS_ETM_RANGE packet after CS_ETM_TRACE_ON packet, this have two purposes, the first one purpose is to save the info for the new CS_ETM_RANGE packet, the second purpose is to save CS_ETM_TRACE_ON packet info so we can have hint for a discontinuity in the trace.

  For CS_ETM_TRACE_ON packet, its fields 'packet->start_addr' and 'packet->end_addr' equal to 0xdeadbeefdeadbeefUL which are emitted in the decoder layer as dummy value. This patch is to convert these values to zeros for more readable; this is accomplished by functions cs_etm__last_executed_instr() and cs_etm__first_executed_instr(). The later one is a new function introduced by this patch.

Reviewed-by: Robert Walker robert.walker@arm.com Fixes: e573e978fb12 ("perf cs-etm: Inject capabilitity for CoreSight traces") Signed-off-by: Leo Yan leo.yan@linaro.org

---

tools/perf/util/cs-etm.c | 93 +++++++++++++++++++++++++++++++++++++----------- 1 file changed, 73 insertions(+), 20 deletions(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 822ba91..8418173 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -495,6 +495,20 @@ static inline void cs_etm__reset_last_branch_rb(struct cs_etm_queue *etmq) static inline u64 cs_etm__last_executed_instr(struct cs_etm_packet *packet) { /*

• * The packet is the start tracing packet if the end_addr is zero,
  

• * returns 0 for this case.
  

• */
  

• if (!packet->end_addr)

• return 0;
  

What is considered to be the "start tracing packet"? Right now the only two kind of packets inserted in the decoder packet buffer queue are INST_RANGE and TRACE_ON. How can we hit a condition where packet->end-addr == 0?

• /*

• * The packet is the CS_ETM_TRACE_ON packet if the end_addr is
  

• * magic number 0xdeadbeefdeadbeefUL, returns 0 for this case.
  

• */
  

• if (packet->end_addr == 0xdeadbeefdeadbeefUL)

• return 0;
  

As it is with the above, I find triggering on addresses to be brittle and hard to maintain on the long run. Packets all have a sample_type field that should be used in cases like this one. That way we know exactly the condition that is targeted.

While working on this set, please spin-off another patch that defines CS_ETM_INVAL_ADDR 0xdeadbeefdeadbeefUL and replace all the cases where the numeral is used. That way we stop using the hard coded value.

• /*
  • The packet records the execution range with an exclusive end address
  • A64 instructions are constant size, so the last executed

@@ -505,6 +519,18 @@ static inline u64 cs_etm__last_executed_instr(struct cs_etm_packet *packet) return packet->end_addr - A64_INSTR_SIZE; } +static inline u64 cs_etm__first_executed_instr(struct cs_etm_packet *packet) +{

• /*

• * The packet is the CS_ETM_TRACE_ON packet if the start_addr is
  

• * magic number 0xdeadbeefdeadbeefUL, returns 0 for this case.
  

• */
  

• if (packet->start_addr == 0xdeadbeefdeadbeefUL)

• return 0;
  

Same comment as above.

• return packet->start_addr;

+}

static inline u64 cs_etm__instr_count(const struct cs_etm_packet *packet) { /* @@ -546,7 +572,7 @@ static void cs_etm__update_last_branch_rb(struct cs_etm_queue *etmq) be = &bs->entries[etmq->last_branch_pos]; be->from = cs_etm__last_executed_instr(etmq->prev_packet);

• be->to = etmq->packet->start_addr;

• be->to = cs_etm__first_executed_instr(etmq->packet); /* No support for mispredict */ be->flags.mispred = 0; be->flags.predicted = 1;

@@ -701,7 +727,7 @@ static int cs_etm__synth_branch_sample(struct cs_etm_queue *etmq) sample.ip = cs_etm__last_executed_instr(etmq->prev_packet); sample.pid = etmq->pid; sample.tid = etmq->tid;

• sample.addr = etmq->packet->start_addr;

• sample.addr = cs_etm__first_executed_instr(etmq->packet); sample.id = etmq->etm->branches_id; sample.stream_id = etmq->etm->branches_id; sample.period = 1;

@@ -897,13 +923,28 @@ static int cs_etm__sample(struct cs_etm_queue *etmq) etmq->period_instructions = instrs_over; }

• if (etm->sample_branches &&

•    etmq->prev_packet &&
  

•    etmq->prev_packet->sample_type == CS_ETM_RANGE &&
  

•    etmq->prev_packet->last_instr_taken_branch) {
  

• ret = cs_etm__synth_branch_sample(etmq);
  

• if (ret)
  

• 	return ret;
  

• if (etm->sample_branches && etmq->prev_packet) {

• bool generate_sample = false;
  

• /* Generate sample for start tracing packet */
  

• if (etmq->prev_packet->sample_type == 0 ||
  

What kind of packet is sample_type == 0 ?

•     etmq->prev_packet->sample_type == CS_ETM_TRACE_ON)
  

• 	generate_sample = true;
  

• /* Generate sample for exception packet */
  

• if (etmq->prev_packet->exc == true)
  

• 	generate_sample = true;
  

Please don't do that. Exception packets have a type of their own and can be added to the decoder packet queue the same way INST_RANGE and TRACE_ON packets are. Moreover exception packet containt an address that, if I'm reading the documenation properly, can be used to keep track of instructions that were executed between the last address of the previous range packet and the address executed just before the exception occurred. Mike and Rob will have to confirm this as the decoder may be doing all that hard work for us.

• /* Generate sample for normal branch packet */
  

• if (etmq->prev_packet->sample_type == CS_ETM_RANGE &&
  

•     etmq->prev_packet->last_instr_taken_branch)
  

• 	generate_sample = true;
  

• if (generate_sample) {
  

• 	ret = cs_etm__synth_branch_sample(etmq);
  

• 	if (ret)
  

• 		return ret;
  

• }
  

  }

if (etm->sample_branches || etm->synth_opts.last_branch) { @@ -922,11 +963,16 @@ static int cs_etm__sample(struct cs_etm_queue *etmq) static int cs_etm__flush(struct cs_etm_queue *etmq) { int err = 0;

• struct cs_etm_auxtrace *etm = etmq->etm; struct cs_etm_packet *tmp;

• if (etmq->etm->synth_opts.last_branch &&

•    etmq->prev_packet &&
  

•    etmq->prev_packet->sample_type == CS_ETM_RANGE) {
  

• if (!etmq->prev_packet)

• return 0;
  

• if (etmq->prev_packet->sample_type != CS_ETM_RANGE)

• return 0;
  

• if (etmq->etm->synth_opts.last_branch) {

If you add:

if (!etmq->etm->synth_opts.last_branch) return 0;

You can avoid indenting the whole block.

/*
 * Generate a last branch event for the branches left in the
 * circular buffer at the end of the trace.

@@ -939,18 +985,25 @@ static int cs_etm__flush(struct cs_etm_queue *etmq) err = cs_etm__synth_instruction_sample( etmq, addr, etmq->period_instructions);

• if (err)
  

• 	return err;
  

  etmq->period_instructions = 0;
• }

• /*
  

•  * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for
  

•  * the next incoming packet.
  

•  */
  

• tmp = etmq->packet;
  

• etmq->packet = etmq->prev_packet;
  

• etmq->prev_packet = tmp;
  

• if (etm->sample_branches) {

• err = cs_etm__synth_branch_sample(etmq);
  

• if (err)
  

• 	return err;
  

  }

• return err;

• /*

• * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for
  

• * the next incoming packet.
  

• */
  

• tmp = etmq->packet;
• etmq->packet = etmq->prev_packet;
• etmq->prev_packet = tmp;

Robert, I remember noticing that when you first submitted the code but forgot to go back to it. What is the point of swapping the packets? I understand

etmq->prev_packet = etmq->packet;

But not

etmq->packet = tmp;

After all etmq->packet will be clobbered as soon as cs_etm_decoder__get_packet() is called, which is alwasy right after either cs_etm__sample() or cs_etm__flush().

Thanks, Mathieu

• return 0;

} static int cs_etm__run_decoder(struct cs_etm_queue *etmq) -- 2.7.4

Hi Mathieu,

On Tue, May 29, 2018 at 10:04:49AM -0600, Mathieu Poirier wrote:

[...]

...

As now this patch is big with more complex logic, so I consider to split it into small patches:

• Define CS_ETM_INVAL_ADDR;
• Fix for CS_ETM_TRACE_ON packet;
• Fix for exception packet;

Does this make sense for you? I have concern that this patch is a fixing patch, so not sure after spliting patches will introduce trouble for applying them for other stable kernels ...

Reverse the order:

• Fix for CS_ETM_TRACE_ON packet;
• Fix for exception packet;
• Define CS_ETM_INVAL_ADDR;

But you may not need to - see next comment.

From the discussion context, I think here 'you may not need to' is

referring to my concern for applying patches on stable kernel, so I should take this patch series as an enhancement and don't need to consider much for stable kernel.

On the other hand, your suggestion is possible to mean 'not need to' split into small patches (though I guess this is misunderstanding for your meaning).

Could you clarify which is your meaning?

...

...

...

• /*
  • The packet records the execution range with an exclusive end address
  • A64 instructions are constant size, so the last executed

@@ -505,6 +519,18 @@ static inline u64 cs_etm__last_executed_instr(struct cs_etm_packet *packet) return packet->end_addr - A64_INSTR_SIZE; }

+static inline u64 cs_etm__first_executed_instr(struct cs_etm_packet *packet) +{

• /*
• • The packet is the CS_ETM_TRACE_ON packet if the start_addr is
• • magic number 0xdeadbeefdeadbeefUL, returns 0 for this case.
• */
• if (packet->start_addr == 0xdeadbeefdeadbeefUL)

•       return 0;
  

Same comment as above.

Will do this.

...

...

• return packet->start_addr;

+}

static inline u64 cs_etm__instr_count(const struct cs_etm_packet *packet) { /* @@ -546,7 +572,7 @@ static void cs_etm__update_last_branch_rb(struct cs_etm_queue *etmq)

be       = &bs->entries[etmq->last_branch_pos];
be->from = cs_etm__last_executed_instr(etmq->prev_packet);

• be->to = etmq->packet->start_addr;

• be->to = cs_etm__first_executed_instr(etmq->packet); /* No support for mispredict */ be->flags.mispred = 0; be->flags.predicted = 1;

@@ -701,7 +727,7 @@ static int cs_etm__synth_branch_sample(struct cs_etm_queue *etmq) sample.ip = cs_etm__last_executed_instr(etmq->prev_packet); sample.pid = etmq->pid; sample.tid = etmq->tid;

• sample.addr = etmq->packet->start_addr;

• sample.addr = cs_etm__first_executed_instr(etmq->packet); sample.id = etmq->etm->branches_id; sample.stream_id = etmq->etm->branches_id; sample.period = 1;

@@ -897,13 +923,28 @@ static int cs_etm__sample(struct cs_etm_queue *etmq) etmq->period_instructions = instrs_over; }

• if (etm->sample_branches &&

•   etmq->prev_packet &&
  

•   etmq->prev_packet->sample_type == CS_ETM_RANGE &&
  

•   etmq->prev_packet->last_instr_taken_branch) {
  

•       ret = cs_etm__synth_branch_sample(etmq);
  

•       if (ret)
  

•               return ret;
  

• if (etm->sample_branches && etmq->prev_packet) {

•       bool generate_sample = false;
  

•       /* Generate sample for start tracing packet */
  

•       if (etmq->prev_packet->sample_type == 0 ||
  

What kind of packet is sample_type == 0 ?

Just as explained above, sample_type == 0 is the packet which initialized in the function cs_etm__alloc_queue().

...

...

•           etmq->prev_packet->sample_type == CS_ETM_TRACE_ON)
  

•               generate_sample = true;
  

•       /* Generate sample for exception packet */
  

•       if (etmq->prev_packet->exc == true)
  

•               generate_sample = true;
  

Please don't do that. Exception packets have a type of their own and can be added to the decoder packet queue the same way INST_RANGE and TRACE_ON packets are. Moreover exception packet containt an address that, if I'm reading the documenation properly, can be used to keep track of instructions that were executed between the last address of the previous range packet and the address executed just before the exception occurred. Mike and Rob will have to confirm this as the decoder may be doing all that hard work for us.

Sure, will wait for Rob and Mike to confirm for this.

At my side, I dump the packet, the exception packet isn't passed to cs-etm.c layer, the decoder layer only sets the flag 'packet->exc = true' when exception packet is coming [1].

That's because we didn't need the information. Now that we do a function that will insert a packet in the decoder packet queue and deal with the new packet type in the main decoder loop [2]. At that point your work may not be eligible for stable anymore and I think it is fine. Robert's work was an enhancement over mine and yours is an enhancement over his.

[2]. https://elixir.bootlin.com/linux/v4.17-rc7/source/tools/perf/util/cs-etm.c#L...

Agree, will look into for exception packet and try to add new packet type for this.

[...]

Thanks, Leo Yan

On 29 May 2018 at 18:28, Leo Yan leo.yan@linaro.org wrote:

Hi Mathieu,

On Tue, May 29, 2018 at 10:04:49AM -0600, Mathieu Poirier wrote:

[...]

...

...

As now this patch is big with more complex logic, so I consider to split it into small patches:

• Define CS_ETM_INVAL_ADDR;
• Fix for CS_ETM_TRACE_ON packet;
• Fix for exception packet;

Does this make sense for you? I have concern that this patch is a fixing patch, so not sure after spliting patches will introduce trouble for applying them for other stable kernels ...

Reverse the order:

• Fix for CS_ETM_TRACE_ON packet;
• Fix for exception packet;
• Define CS_ETM_INVAL_ADDR;

But you may not need to - see next comment.

From the discussion context, I think here 'you may not need to' is referring to my concern for applying patches on stable kernel, so I should take this patch series as an enhancement and don't need to consider much for stable kernel.

Yes, that is what I meant.

On the other hand, your suggestion is possible to mean 'not need to' split into small patches (though I guess this is misunderstanding for your meaning).

Could you clarify which is your meaning?

...

...

...

...

• /*
  • The packet records the execution range with an exclusive end address
  • A64 instructions are constant size, so the last executed

@@ -505,6 +519,18 @@ static inline u64 cs_etm__last_executed_instr(struct cs_etm_packet *packet) return packet->end_addr - A64_INSTR_SIZE; }

+static inline u64 cs_etm__first_executed_instr(struct cs_etm_packet *packet) +{

• /*
• • The packet is the CS_ETM_TRACE_ON packet if the start_addr is
• • magic number 0xdeadbeefdeadbeefUL, returns 0 for this case.
• */
• if (packet->start_addr == 0xdeadbeefdeadbeefUL)

•       return 0;
  

Same comment as above.

Will do this.

...

...

• return packet->start_addr;

+}

static inline u64 cs_etm__instr_count(const struct cs_etm_packet *packet) { /* @@ -546,7 +572,7 @@ static void cs_etm__update_last_branch_rb(struct cs_etm_queue *etmq)

be       = &bs->entries[etmq->last_branch_pos];
be->from = cs_etm__last_executed_instr(etmq->prev_packet);

• be->to = etmq->packet->start_addr;

• be->to = cs_etm__first_executed_instr(etmq->packet); /* No support for mispredict */ be->flags.mispred = 0; be->flags.predicted = 1;

@@ -701,7 +727,7 @@ static int cs_etm__synth_branch_sample(struct cs_etm_queue *etmq) sample.ip = cs_etm__last_executed_instr(etmq->prev_packet); sample.pid = etmq->pid; sample.tid = etmq->tid;

• sample.addr = etmq->packet->start_addr;

• sample.addr = cs_etm__first_executed_instr(etmq->packet); sample.id = etmq->etm->branches_id; sample.stream_id = etmq->etm->branches_id; sample.period = 1;

@@ -897,13 +923,28 @@ static int cs_etm__sample(struct cs_etm_queue *etmq) etmq->period_instructions = instrs_over; }

• if (etm->sample_branches &&

•   etmq->prev_packet &&
  

•   etmq->prev_packet->sample_type == CS_ETM_RANGE &&
  

•   etmq->prev_packet->last_instr_taken_branch) {
  

•       ret = cs_etm__synth_branch_sample(etmq);
  

•       if (ret)
  

•               return ret;
  

• if (etm->sample_branches && etmq->prev_packet) {

•       bool generate_sample = false;
  

•       /* Generate sample for start tracing packet */
  

•       if (etmq->prev_packet->sample_type == 0 ||
  

What kind of packet is sample_type == 0 ?

Just as explained above, sample_type == 0 is the packet which initialized in the function cs_etm__alloc_queue().

...

...

•           etmq->prev_packet->sample_type == CS_ETM_TRACE_ON)
  

•               generate_sample = true;
  

•       /* Generate sample for exception packet */
  

•       if (etmq->prev_packet->exc == true)
  

•               generate_sample = true;
  

Please don't do that. Exception packets have a type of their own and can be added to the decoder packet queue the same way INST_RANGE and TRACE_ON packets are. Moreover exception packet containt an address that, if I'm reading the documenation properly, can be used to keep track of instructions that were executed between the last address of the previous range packet and the address executed just before the exception occurred. Mike and Rob will have to confirm this as the decoder may be doing all that hard work for us.

Sure, will wait for Rob and Mike to confirm for this.

At my side, I dump the packet, the exception packet isn't passed to cs-etm.c layer, the decoder layer only sets the flag 'packet->exc = true' when exception packet is coming [1].

That's because we didn't need the information. Now that we do a function that will insert a packet in the decoder packet queue and deal with the new packet type in the main decoder loop [2]. At that point your work may not be eligible for stable anymore and I think it is fine. Robert's work was an enhancement over mine and yours is an enhancement over his.

[2]. https://elixir.bootlin.com/linux/v4.17-rc7/source/tools/perf/util/cs-etm.c#L...

Agree, will look into for exception packet and try to add new packet type for this.

[...]

Thanks, Leo Yan

Hi Leo,

On 30 May 2018 at 10:45, Robert Walker robert.walker@arm.com wrote:

On 28/05/18 23:13, Mathieu Poirier wrote:

...

Leo and/or Robert,

On Mon, May 28, 2018 at 04:45:00PM +0800, Leo Yan wrote:

...

Commit e573e978fb12 ("perf cs-etm: Inject capabilitity for CoreSight traces") reworks the samples generation flow from CoreSight trace to match the correct format so Perf report tool can display the samples properly.

But the change has side effect for branch packet handling, it only generate branch samples by checking previous packet flag 'last_instr_taken_branch' is true, this results in below three kinds packets are missed to generate branch samples:

• The start tracing packet at the beginning of tracing data;
• The exception handling packet;
• If one CS_ETM_TRACE_ON packet is inserted, we also miss to handle it for branch samples. CS_ETM_TRACE_ON packet itself can give the info that there have a discontinuity in the trace, on the other hand we also miss to generate proper branch sample for packets before and after CS_ETM_TRACE_ON packet.

This patch is to add branch sample handling for up three kinds packets:

• In function cs_etm__sample(), check if 'prev_packet->sample_type' is zero and in this case it generates branch sample for the start tracing packet; furthermore, we also need to handle the condition for prev_packet::end_addr is zero in the cs_etm__last_executed_instr();

• In function cs_etm__sample(), check if 'prev_packet->exc' is true and generate branch sample for exception handling packet;

• If there has one CS_ETM_TRACE_ON packet is coming, we firstly generate branch sample in the function cs_etm__flush(), this can save complete info for the previous CS_ETM_RANGE packet just before CS_ETM_TRACE_ON packet. We also generate branch sample for the new CS_ETM_RANGE packet after CS_ETM_TRACE_ON packet, this have two purposes, the first one purpose is to save the info for the new CS_ETM_RANGE packet, the second purpose is to save CS_ETM_TRACE_ON packet info so we can have hint for a discontinuity in the trace.

  For CS_ETM_TRACE_ON packet, its fields 'packet->start_addr' and 'packet->end_addr' equal to 0xdeadbeefdeadbeefUL which are emitted in the decoder layer as dummy value. This patch is to convert these values to zeros for more readable; this is accomplished by functions cs_etm__last_executed_instr() and cs_etm__first_executed_instr(). The later one is a new function introduced by this patch.

Reviewed-by: Robert Walker robert.walker@arm.com Fixes: e573e978fb12 ("perf cs-etm: Inject capabilitity for CoreSight traces") Signed-off-by: Leo Yan leo.yan@linaro.org

---

tools/perf/util/cs-etm.c | 93 +++++++++++++++++++++++++++++++++++++----------- 1 file changed, 73 insertions(+), 20 deletions(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 822ba91..8418173 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -495,6 +495,20 @@ static inline void cs_etm__reset_last_branch_rb(struct cs_etm_queue *etmq) static inline u64 cs_etm__last_executed_instr(struct cs_etm_packet *packet) { /*

•    * The packet is the start tracing packet if the end_addr is
  

zero,

•    * returns 0 for this case.
  

•    */
  

•   if (!packet->end_addr)
  

•           return 0;
  

What is considered to be the "start tracing packet"? Right now the only two kind of packets inserted in the decoder packet buffer queue are INST_RANGE and TRACE_ON. How can we hit a condition where packet->end-addr == 0?

...

•   /*
  

•    * The packet is the CS_ETM_TRACE_ON packet if the end_addr is
  

•    * magic number 0xdeadbeefdeadbeefUL, returns 0 for this case.
  

•    */
  

•   if (packet->end_addr == 0xdeadbeefdeadbeefUL)
  

•           return 0;
  

As it is with the above, I find triggering on addresses to be brittle and hard to maintain on the long run. Packets all have a sample_type field that should be used in cases like this one. That way we know exactly the condition that is targeted.

While working on this set, please spin-off another patch that defines CS_ETM_INVAL_ADDR 0xdeadbeefdeadbeefUL and replace all the cases where the numeral is used. That way we stop using the hard coded value.

...

•   /*
     * The packet records the execution range with an exclusive end
  

address * * A64 instructions are constant size, so the last executed @@ -505,6 +519,18 @@ static inline u64 cs_etm__last_executed_instr(struct cs_etm_packet *packet) return packet->end_addr - A64_INSTR_SIZE; } +static inline u64 cs_etm__first_executed_instr(struct cs_etm_packet *packet) +{

•   /*
  

•    * The packet is the CS_ETM_TRACE_ON packet if the start_addr is
  

•    * magic number 0xdeadbeefdeadbeefUL, returns 0 for this case.
  

•    */
  

•   if (packet->start_addr == 0xdeadbeefdeadbeefUL)
  

•           return 0;
  

Same comment as above.

...

•   return packet->start_addr;
  

+}

• static inline u64 cs_etm__instr_count(const struct cs_etm_packet

*packet) { /* @@ -546,7 +572,7 @@ static void cs_etm__update_last_branch_rb(struct cs_etm_queue *etmq) be = &bs->entries[etmq->last_branch_pos]; be->from = cs_etm__last_executed_instr(etmq->prev_packet);

•   be->to   = etmq->packet->start_addr;
  

•   be->to   = cs_etm__first_executed_instr(etmq->packet);
    /* No support for mispredict */
    be->flags.mispred = 0;
    be->flags.predicted = 1;
  

@@ -701,7 +727,7 @@ static int cs_etm__synth_branch_sample(struct cs_etm_queue *etmq) sample.ip = cs_etm__last_executed_instr(etmq->prev_packet); sample.pid = etmq->pid; sample.tid = etmq->tid;

•   sample.addr = etmq->packet->start_addr;
  

•   sample.addr = cs_etm__first_executed_instr(etmq->packet);
    sample.id = etmq->etm->branches_id;
    sample.stream_id = etmq->etm->branches_id;
    sample.period = 1;
  

@@ -897,13 +923,28 @@ static int cs_etm__sample(struct cs_etm_queue *etmq) etmq->period_instructions = instrs_over; }

• if (etm->sample_branches &&
  

•       etmq->prev_packet &&
  

•       etmq->prev_packet->sample_type == CS_ETM_RANGE &&
  

•       etmq->prev_packet->last_instr_taken_branch) {
  

•           ret = cs_etm__synth_branch_sample(etmq);
  

•           if (ret)
  

•                   return ret;
  

•   if (etm->sample_branches && etmq->prev_packet) {
  

•           bool generate_sample = false;
  

•           /* Generate sample for start tracing packet */
  

•           if (etmq->prev_packet->sample_type == 0 ||
  

What kind of packet is sample_type == 0 ?

...

•               etmq->prev_packet->sample_type == CS_ETM_TRACE_ON)
  

•                   generate_sample = true;
  

•           /* Generate sample for exception packet */
  

•           if (etmq->prev_packet->exc == true)
  

•                   generate_sample = true;
  

Please don't do that. Exception packets have a type of their own and can be added to the decoder packet queue the same way INST_RANGE and TRACE_ON packets are. Moreover exception packet containt an address that, if I'm reading the documenation properly, can be used to keep track of instructions that were executed between the last address of the previous range packet and the address executed just before the exception occurred. Mike and Rob will have to confirm this as the decoder may be doing all that hard work for us.

clarification on the exception packets....

The Opencsd output exception packet gives you the exception number, and optionally the preferred return address. If this address is present does depend a lot on the underlying protocol - will normally be there with ETMv4. Exceptions are marked differently in the underlying protocol - the OCSD packets abstract away these differences.

consider the code:

0x1000: <some instructions> 0x1100: BR 0x2000 .... 0x2000: <some instructions> 0x2020 BZ r4

Without an exception this would result in the packets

OCSD_RANGE(0x1000,0x1104, Last instr type=Br, taken) // recall that range packets have start addr inclusive, end addr exclusive. OCSD_RANGE(0x2000,0x2024, Last instr type=Br, <taken / not taken - depends on condition>

Now consider an exception occurring before the BR 0x2000

this will result in:- OCSD_RANGE(0x1000, 0x1100, Last instr type=Other) OCSD_EXECEPTION(IRQ, ret-addr 0x1100) OCSD_RANGE(IRQ_START, IRQ_END+4, Last instr type = BR, taken) // this is more likely to have multiple ranges / branches before any return, but simplified here. OCSD_EXCEPTION_RETURN() // present if exception returns are explicitly marked in underlying trace - may not always be depending on circumstances. OCSD_RANGE(0x1100,0x1104, Last=BR, taken) // continue on with short range - just the branch OCSD_RANGE(0x2000,0x2024, Last instr type=Br, <taken / not taken - depends on condition>

Now consider the exception occurring after the BR, but before any other instructions are executed.

OCSD_RANGE(0x1000,0x1104, Last instr type=Br, taken) // recall that range packets have start addr inclusive, end addr exclusive. OCSD_EXECEPTION(IRQ, ret-addr 0x2000) // here the preferred return address is actually the target of the branch. OCSD_RANGE(IRQ_START, IRQ_END+4, Last instr type = BR, taken) // this is more likely to have multiple ranges / branches before any return, but simplified here. OCSD_RANGE(0x2000,0x2024, Last instr type=Br, <taken / not taken - depends on condition>

So in general it is possible to arrive in the IRQ_START range with the previous packet having been either a taken branch, a not taken branch, or not a branch. Care must be taken - whether AutoFDO or normal trace disassembly not to assume that having the last range packet as a taken branch means that the next range packet is the target, if there is an intervening exception packet.

Regards

Mike

...

...

•           /* Generate sample for normal branch packet */
  

•           if (etmq->prev_packet->sample_type == CS_ETM_RANGE &&
  

•               etmq->prev_packet->last_instr_taken_branch)
  

•                   generate_sample = true;
  

•           if (generate_sample) {
  

•                   ret = cs_etm__synth_branch_sample(etmq);
  

•                   if (ret)
  

•                           return ret;
  

•           }
    }
    if (etm->sample_branches || etm->synth_opts.last_branch) {
  

@@ -922,11 +963,16 @@ static int cs_etm__sample(struct cs_etm_queue *etmq) static int cs_etm__flush(struct cs_etm_queue *etmq) { int err = 0;

•   struct cs_etm_auxtrace *etm = etmq->etm;
    struct cs_etm_packet *tmp;
  

  • if (etmq->etm->synth_opts.last_branch &&
    

•       etmq->prev_packet &&
  

•       etmq->prev_packet->sample_type == CS_ETM_RANGE) {
  

•   if (!etmq->prev_packet)
  

•           return 0;
  

•   if (etmq->prev_packet->sample_type != CS_ETM_RANGE)
  

•           return 0;
  

•   if (etmq->etm->synth_opts.last_branch) {
  

If you add:

     if (!etmq->etm->synth_opts.last_branch)
             return 0;

You can avoid indenting the whole block.

...

            /*
             * Generate a last branch event for the branches left in

the * circular buffer at the end of the trace. @@ -939,18 +985,25 @@ static int cs_etm__flush(struct cs_etm_queue *etmq) err = cs_etm__synth_instruction_sample( etmq, addr, etmq->period_instructions);

•           if (err)
  

•                   return err;
            etmq->period_instructions = 0;
  

•   }
  

  •         /*
    

•            * Swap PACKET with PREV_PACKET: PACKET becomes
  

PREV_PACKET for

•            * the next incoming packet.
  

•            */
  

•           tmp = etmq->packet;
  

•           etmq->packet = etmq->prev_packet;
  

•           etmq->prev_packet = tmp;
  

•   if (etm->sample_branches) {
  

•           err = cs_etm__synth_branch_sample(etmq);
  

•           if (err)
  

•                   return err;
    }
  

  • return err;
    

•   /*
  

•    * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for
  

•    * the next incoming packet.
  

•    */
  

•   tmp = etmq->packet;
  

•   etmq->packet = etmq->prev_packet;
  

•   etmq->prev_packet = tmp;
  

Robert, I remember noticing that when you first submitted the code but forgot to go back to it. What is the point of swapping the packets? I understand

etmq->prev_packet = etmq->packet;

But not

etmq->packet = tmp;

After all etmq->packet will be clobbered as soon as cs_etm_decoder__get_packet() is called, which is alwasy right after either cs_etm__sample() or cs_etm__flush().

This is code I inherited from the original versions of these patches, but it works because:

• etmq->packet and etmq->prev_packet are pointers to struct cs_etm_packet

allocated by zalloc() in cs_etm__alloc_queue()

• cs_etm_decoder__get_packet() takes a pointer to struct cs_etm_packet and

copies the contents of the first packet from the queue into the passed location with: *packet = decoder->packet_buffer[decoder->head]

So the swap code is only swapping the pointers over, not the contents of the packets.

Regards

Rob

...

Thanks, Mathieu

...

•   return 0;
  

  } static int cs_etm__run_decoder(struct cs_etm_queue *etmq)

-- 2.7.4