CoreSight June 2018

coresight@lists.linaro.org

20 participants
16 discussions

[PATCH 00/12] perf tools: Add support for CoreSight CPU-wide session

by Mathieu Poirier

This set adds support for CoreSight CPU-wide trace sessions. It borrows most of its code from the per-thread implementation with exception that range packets are processed and synthesised according to the time the trace they contain has been executed. This is done using the timestamp and contextID feature available on ETM4x tracers (ETM3x/PTM aren't addressed yet). Decoding between processors is done in chronological order using a min heap. Of special interest is the way timestamp packets are used to account for temporal execution of traced instructions. Since a timestamp typically happen after range packets have been recorded, the timestamp from the previous range is used as the start time of the current range. When a timestamp for the previous range doesn't exist (i.e start of trace or discontinuity) the start time is estimated. Open question: -------------- At this time the implementation supports tracing a single CPU since the only HW we have exhibit an N:1 source/sink topology. The HW itself does support collecting traces from more than one source but using the feature in this way could be very confusing and mislead users. For example the following: # perf record -e cs_etm/20070000.etr/ -C 2,3 application1 would end up tracing everyting that is happening on CPU 2 and 3 for as long as appliation1 is executing. Because the HW doesn't give us an interrupt when buffers are full, traces from one CPU could easily clobber traces from the other, giving the impression that nothing was executed on the latter. So this would work: # perf record -e cs_etm/20070000.etr/ -C 3 application1 I am open to discussion on the topic should someone think of something. As with the cleanup set this code has been uploaded here [1]. Thanks, Mathieu [1].https://git.linaro.org/people/mathieu.poirier/coresight.git perf-opencsd-master-cpu-wide-support Mathieu Poirier (12): perf tools: Add defines for CONTEXTID configuration perf tools: Configure contextID tracing in CPU-wide mode perf tools: Configure timestsamp generation in CPU-wide mode perf tools: Configure SWITCH_EVENTS in CPU-wide mode perf tools: Add handling of itrace start events perf tools: Add handling of switch-CPU-wide events perf tools: Linking PE contextID with perf thread mechanic perf tools: Allocate decoder tree as needed perf tools: Make cs_etm__dump_event() work with CPU-wide scenarios perf tools: Add notion of time to the decoding code perf tools: Make function cs_etm_decoder__clear_buffer() public perf tools: Add support for CPU-wide trace scenarios include/linux/coresight-pmu.h | 2 + tools/include/linux/coresight-pmu.h | 2 + tools/perf/arch/arm/util/cs-etm.c | 174 ++++++++++-- tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 140 +++++++++- tools/perf/util/cs-etm-decoder/cs-etm-decoder.h | 4 +- tools/perf/util/cs-etm.c | 334 ++++++++++++++++++++++-- tools/perf/util/cs-etm.h | 17 ++ 7 files changed, 623 insertions(+), 50 deletions(-) -- 2.7.4

6 years, 6 months

Regression of 'perf record' on Hikey620

by Leo Yan

Hi all, Just in case you have the same issue, when I use acme's branch perf/core with latest commit e238cf2e3d2e ("perf intel-pt: Fix packet decoding of CYC packets"), I can easily reproduce below failure with 'perf record' command. If you have fixing for this, please let me know. Otherwise I will dig a bit for this issue (probably relying on 'git bisect'). Thanks, Leo Yan ---8<--- # ./perf record -e cs_etm/(a)f6402000.etf/ --per-thread uname [ 240.623458] Internal error: synchronous external abort: 96000210 [#10] PREEMPT SMP [ 240.631055] Modules linked in: [ 240.634117] CPU: 1 PID: 2793 Comm: perf Tainted: G D 4.17.0-08502-ge238cf2 #26 [ 240.642648] Hardware name: HiKey Development Board (DT) [ 240.647876] pstate: 40000005 (nZcv daif -PAN -UAO) [ 240.652677] pc : trcauthstatus_show+0x3c/0x78 [ 240.657035] lr : trcauthstatus_show+0x34/0x78 [ 240.661391] sp : ffff00000dcfbbc0 [ 240.664703] x29: ffff00000dcfbbc0 x28: 0000000000000001 [ 240.670019] x27: 00000000007000c0 x26: ffff800036fa4048 [ 240.675335] x25: 0000000000001000 x24: ffff000008d95330 [ 240.680651] x23: ffff8000372ad880 x22: ffff80003b346cb8 [ 240.685966] x21: ffff800036fa8080 x20: ffff80003b346ca8 [ 240.691281] x19: ffff0000099d5fb8 x18: 0000000000000000 [ 240.696597] x17: 0000ffffbb44bb68 x16: ffff0000082a3908 [ 240.701911] x15: 0000000000000000 x14: 0000000000000016 [ 240.707227] x13: 7375746174736874 x12: 75616372742f746d [ 240.712542] x11: 0000000000000020 x10: 0000000080070007 [ 240.717857] x9 : 0000000000000000 x8 : ffff800036fa9080 [ 240.723173] x7 : 0000000000000000 x6 : 000000000000003f [ 240.728488] x5 : 0000000000000040 x4 : 0000000000000000 [ 240.733803] x3 : 0000000000000000 x2 : 4d223a68697bbd00 [ 240.739118] x1 : ffff80001fc30f80 x0 : 0000000000000001 [ 240.744435] Process perf (pid: 2793, stack limit = 0x0000000051ca53e7) [ 240.750965] Call trace: [ 240.753411] trcauthstatus_show+0x3c/0x78 [ 240.757423] dev_attr_show+0x3c/0x80 [ 240.761002] sysfs_kf_seq_show+0xc0/0x158 [ 240.765012] kernfs_seq_show+0x44/0x50 [ 240.768764] seq_read+0x1cc/0x4b8 [ 240.772078] kernfs_fop_read+0x13c/0x1e0 [ 240.776002] __vfs_read+0x60/0x170 [ 240.779403] vfs_read+0x94/0x150 [ 240.782630] ksys_read+0x6c/0xd8 [ 240.785856] sys_read+0x34/0x48 [ 240.788998] el0_svc_naked+0x30/0x34 [ 240.792575] Code: f9404c53 97f2054e f9400273 913ee273 (b9400273) [ 240.798673] ---[ end trace 838ff5bf36115622 ]--- Message from syslogd@linaro-developer at May 23 09:50:03 ... kernel:[ 240.623458] Internal error: synchronous external abort: 96000210 [#10] PREEMPT SMP Message from syslogd@linaro-developer at May 23 09:50:03 ... kernel:[ 240.744435] Process perf (pid: 2793, stack limit = 0x0000000051ca53e7) Message from syslogd@linaro-developer at May 23 09:50:03 ... kernel:[ 240.792575] Code: f9404c53 97f2054e f9400273 913ee273 (b9400273) Segmentation fault root@linaro-developer:~#

6 years, 6 months

[PATCH v1 1/6] perf cs-etm: Introduce invalid address macro

by Leo Yan

This patch introduces invalid address macro and uses it to replace dummy value '0xdeadbeefdeadbeefUL'. Signed-off-by: Leo Yan <leo.yan(a)linaro.org> --- tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 8 ++++---- tools/perf/util/cs-etm-decoder/cs-etm-decoder.h | 2 ++ 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c index 4d5fc37..24aabf0 100644 --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c @@ -261,8 +261,8 @@ static void cs_etm_decoder__clear_buffer(struct cs_etm_decoder *decoder) decoder->tail = 0; decoder->packet_count = 0; for (i = 0; i < MAX_BUFFER; i++) { - decoder->packet_buffer[i].start_addr = 0xdeadbeefdeadbeefUL; - decoder->packet_buffer[i].end_addr = 0xdeadbeefdeadbeefUL; + decoder->packet_buffer[i].start_addr = CS_ETM_INVAL_ADDR; + decoder->packet_buffer[i].end_addr = CS_ETM_INVAL_ADDR; decoder->packet_buffer[i].last_instr_taken_branch = false; decoder->packet_buffer[i].exc = false; decoder->packet_buffer[i].exc_ret = false; @@ -295,8 +295,8 @@ cs_etm_decoder__buffer_packet(struct cs_etm_decoder *decoder, decoder->packet_buffer[et].exc = false; decoder->packet_buffer[et].exc_ret = false; decoder->packet_buffer[et].cpu = *((int *)inode->priv); - decoder->packet_buffer[et].start_addr = 0xdeadbeefdeadbeefUL; - decoder->packet_buffer[et].end_addr = 0xdeadbeefdeadbeefUL; + decoder->packet_buffer[et].start_addr = CS_ETM_INVAL_ADDR; + decoder->packet_buffer[et].end_addr = CS_ETM_INVAL_ADDR; if (decoder->packet_count == MAX_BUFFER - 1) return OCSD_RESP_WAIT; diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h index 743f5f4..cb31b19 100644 --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h @@ -13,6 +13,8 @@ #include <linux/types.h> #include <stdio.h> +#define CS_ETM_INVAL_ADDR 0xdeadbeefdeadbeefUL + struct cs_etm_decoder; struct cs_etm_buffer { -- 2.7.4

6 years, 6 months

[RFT v4 1/3] perf cs-etm: Generate branch sample for exception packet

by Leo Yan

The exception packet appears as one element with 'elem_type' == OCSD_GEN_TRC_ELEM_EXCEPTION or OCSD_GEN_TRC_ELEM_EXCEPTION_RET, which present for exception entry and exit respectively. The decoder set packet fields 'packet->exc' and 'packet->exc_ret' to indicate the exception packets; but exception packets don't have dedicated sample type and shares the same sample type CS_ETM_RANGE with normal instruction packets. As result, the exception packets are taken as normal instruction packets and this introduces confusion to mix different packet types. Furthermore, these instruction range packets will be processed for branch sample only when 'packet->last_instr_taken_branch' is true, otherwise they will be omitted, this can introduce mess for exception and exception returning due we don't have complete address range info for context switching. To process exception packets properly, this patch introduce two new sample type: CS_ETM_EXCEPTION and CS_ETM_EXCEPTION_RET; for these two kind packets, they will be handled by cs_etm__exception(). The func cs_etm__exception() forces to set previous CS_ETM_RANGE packet flag 'prev_packet->last_instr_taken_branch' to true, this matches well with the program flow when the exception is trapped from user space to kernel space, no matter if the most recent flow has branch taken or not; this is also safe for returning to user space after exception handling. After exception packets have their own sample type, the packet fields 'packet->exc' and 'packet->exc_ret' aren't needed anymore, so remove them. Signed-off-by: Leo Yan <leo.yan(a)linaro.org> --- tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 26 +++++++++++++++++------ tools/perf/util/cs-etm-decoder/cs-etm-decoder.h | 10 ++++----- tools/perf/util/cs-etm.c | 28 +++++++++++++++++++++++++ 3 files changed, 53 insertions(+), 11 deletions(-) diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c index 24aabf0..c1715ff 100644 --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c @@ -264,8 +264,6 @@ static void cs_etm_decoder__clear_buffer(struct cs_etm_decoder *decoder) decoder->packet_buffer[i].start_addr = CS_ETM_INVAL_ADDR; decoder->packet_buffer[i].end_addr = CS_ETM_INVAL_ADDR; decoder->packet_buffer[i].last_instr_taken_branch = false; - decoder->packet_buffer[i].exc = false; - decoder->packet_buffer[i].exc_ret = false; decoder->packet_buffer[i].cpu = INT_MIN; } } @@ -292,8 +290,6 @@ cs_etm_decoder__buffer_packet(struct cs_etm_decoder *decoder, decoder->packet_count++; decoder->packet_buffer[et].sample_type = sample_type; - decoder->packet_buffer[et].exc = false; - decoder->packet_buffer[et].exc_ret = false; decoder->packet_buffer[et].cpu = *((int *)inode->priv); decoder->packet_buffer[et].start_addr = CS_ETM_INVAL_ADDR; decoder->packet_buffer[et].end_addr = CS_ETM_INVAL_ADDR; @@ -345,6 +341,22 @@ cs_etm_decoder__buffer_trace_on(struct cs_etm_decoder *decoder, CS_ETM_TRACE_ON); } +static ocsd_datapath_resp_t +cs_etm_decoder__buffer_exception(struct cs_etm_decoder *decoder, + const uint8_t trace_chan_id) +{ + return cs_etm_decoder__buffer_packet(decoder, trace_chan_id, + CS_ETM_EXCEPTION); +} + +static ocsd_datapath_resp_t +cs_etm_decoder__buffer_exception_ret(struct cs_etm_decoder *decoder, + const uint8_t trace_chan_id) +{ + return cs_etm_decoder__buffer_packet(decoder, trace_chan_id, + CS_ETM_EXCEPTION_RET); +} + static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer( const void *context, const ocsd_trc_index_t indx __maybe_unused, @@ -370,10 +382,12 @@ static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer( trace_chan_id); break; case OCSD_GEN_TRC_ELEM_EXCEPTION: - decoder->packet_buffer[decoder->tail].exc = true; + resp = cs_etm_decoder__buffer_exception(decoder, + trace_chan_id); break; case OCSD_GEN_TRC_ELEM_EXCEPTION_RET: - decoder->packet_buffer[decoder->tail].exc_ret = true; + resp = cs_etm_decoder__buffer_exception_ret(decoder, + trace_chan_id); break; case OCSD_GEN_TRC_ELEM_PE_CONTEXT: case OCSD_GEN_TRC_ELEM_EO_TRACE: diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h index 108dc9d..cb57756 100644 --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h @@ -25,9 +25,11 @@ struct cs_etm_buffer { }; enum cs_etm_sample_type { - CS_ETM_EMPTY = 0, - CS_ETM_RANGE = 1 << 0, - CS_ETM_TRACE_ON = 1 << 1, + CS_ETM_EMPTY = 0, + CS_ETM_RANGE = 1 << 0, + CS_ETM_TRACE_ON = 1 << 1, + CS_ETM_EXCEPTION = 1 << 2, + CS_ETM_EXCEPTION_RET = 1 << 3, }; struct cs_etm_packet { @@ -35,8 +37,6 @@ struct cs_etm_packet { u64 start_addr; u64 end_addr; u8 last_instr_taken_branch; - u8 exc; - u8 exc_ret; int cpu; }; diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 2ae6402..b85100b 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -942,6 +942,25 @@ static int cs_etm__sample(struct cs_etm_queue *etmq) return 0; } +static int cs_etm__exception(struct cs_etm_queue *etmq) +{ + /* + * When the exception packet is inserted, whether the last instruction + * in previous range packet is taken branch or not, we need to force + * to set 'prev_packet->last_instr_taken_branch' to true. This ensures + * to generate branch sample for the instruction range before the + * exception is trapped to kernel or before the exception returning. + * + * The exception packet includes the dummy address values, so don't + * swap PACKET with PREV_PACKET. This keeps PREV_PACKET to be useful + * for generating instruction and branch samples. + */ + if (etmq->prev_packet->sample_type == CS_ETM_RANGE) + etmq->prev_packet->last_instr_taken_branch = true; + + return 0; +} + static int cs_etm__flush(struct cs_etm_queue *etmq) { int err = 0; @@ -1057,6 +1076,15 @@ static int cs_etm__run_decoder(struct cs_etm_queue *etmq) */ cs_etm__sample(etmq); break; + case CS_ETM_EXCEPTION: + case CS_ETM_EXCEPTION_RET: + /* + * If the exception packet is coming, + * make sure the previous instruction + * range packet to be handled properly. + */ + cs_etm__exception(etmq); + break; case CS_ETM_TRACE_ON: /* * Discontinuity in trace, flush -- 2.7.4

6 years, 6 months

[RFT v4 1/8] perf cs-etm: Fix start tracing packet handling

by Leo Yan

Usually the start tracing packet is a CS_ETM_TRACE_ON packet, this packet is passed to cs_etm__flush(); cs_etm__flush() will check the condition 'prev_packet->sample_type == CS_ETM_RANGE' but 'prev_packet' is allocated by zalloc() so 'prev_packet->sample_type' is zero in initialization and this condition is false. So cs_etm__flush() will directly bail out without handling the start tracing packet. This patch is to introduce a new sample type CS_ETM_EMPTY, which is used to indicate the packet is an empty packet. cs_etm__flush() will swap packets when it finds the previous packet is empty, so this can record the start tracing packet into 'etmq->prev_packet'. Another minor change in cs_etm__flush() is to check the condition 'etmq->prev_packet->sample_type == CS_ETM_TRACE_ON', if the previous packet is also a CS_ETM_TRACE_ON packet, the function will skip for contiguous CS_ETM_TRACE_ON packet. Signed-off-by: Leo Yan <leo.yan(a)linaro.org> --- tools/perf/util/cs-etm-decoder/cs-etm-decoder.h | 1 + tools/perf/util/cs-etm.c | 26 ++++++++++++++++++++++--- 2 files changed, 24 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h index 743f5f4..612b575 100644 --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h @@ -23,6 +23,7 @@ struct cs_etm_buffer { }; enum cs_etm_sample_type { + CS_ETM_EMPTY = 0, CS_ETM_RANGE = 1 << 0, CS_ETM_TRACE_ON = 1 << 1, }; diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 822ba91..67564c1 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -924,9 +924,18 @@ static int cs_etm__flush(struct cs_etm_queue *etmq) int err = 0; 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; + + /* Skip for contiguous CS_ETM_TRACE_ON packet */ + if (etmq->prev_packet->sample_type == CS_ETM_TRACE_ON) + return 0; + + /* Handle start tracing packet */ + if (etmq->prev_packet->sample_type == CS_ETM_EMPTY) + goto swap_packet; + + 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. @@ -941,6 +950,10 @@ static int cs_etm__flush(struct cs_etm_queue *etmq) etmq->period_instructions); etmq->period_instructions = 0; + } + +swap_packet: + if (etmq->etm->synth_opts.last_branch) { /* * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for * the next incoming packet. @@ -1020,6 +1033,13 @@ static int cs_etm__run_decoder(struct cs_etm_queue *etmq) */ cs_etm__flush(etmq); break; + case CS_ETM_EMPTY: + /* + * Should not receive empty packet, + * report error. + */ + pr_err("CS ETM Trace: empty packet\n"); + return -EINVAL; default: break; } -- 2.7.4

6 years, 6 months

[RFT v4 0/6] Perf script: Add python script for CoreSight trace disassembler

by Leo Yan

This patch series is to support for using 'perf script' for CoreSight trace disassembler, for this purpose this patch series adds a new python script to parse CoreSight tracing event and use command 'objdump' for disassembled lines, finally this can generate readable program execution flow for reviewing tracing data. Patches 0001 ~ 0003 are to generate samples for the start packet, CS_ETM_TRACE_ON packet and exception packets. Patch 0004 is to introduce invalid address macro. Patch 0005 is to add python script for trace disassembler. Patch 0006 is to add doc to explain python script usage and give example for it. This patch series has been rebased on acme git tree [1] with the latest commit e9175538c04f ("perf script python: Add addr into perf sample dict") and tested on Hikey (ARM64 octa CA53 cores). In this version the script has no dependency on ARM64 platform and is expected to support ARM32 platform, but I am lacking ARM32 platform for testing on it, so firstly upstream to support ARM64 platform. This patch series is firstly to support 'per-thread' recording tracing data, and it has been verified for kernel panic kdump tracing data. Please note, this patch series (v4) is ONLY used for discussion for packet handling, after we get solid result I will send to LKML for reviewing and merging into mainline kernel. Changes from v3: * Split packet handling for three patches, one is for start tracing packet, one is for CS_ETM_TRACE_ON packet and the last one patch is for exception packet; * Introduce invalid address macro. Changes from v2: * Synced with Rob for handling CS_ETM_TRACE_ON packet, so refined 0001 patch according to dicussion; * Minor cleanup and fixes in 0003 patch for python script: remove 'svc' checking. Changes from v1: * According to Mike and Rob suggestion, add the fixing to generate samples for the start packet and exception packets. * Simplify the python script to remove the exception prediction algorithm, we can rely on the sane exception packets for disassembler. Leo Yan (6): perf cs-etm: Fix start tracing packet handling perf cs-etm: Generate branch sample for CS_ETM_TRACE_ON packet perf cs-etm: Generate branch sample for exception packet perf cs-etm: Introduce invalid address macro perf script python: Add script for CoreSight trace disassembler coresight: Document for CoreSight trace disassembler Documentation/trace/coresight.txt | 52 +++++ tools/perf/scripts/python/arm-cs-trace-disasm.py | 235 +++++++++++++++++++++++ tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 19 +- tools/perf/util/cs-etm-decoder/cs-etm-decoder.h | 11 +- tools/perf/util/cs-etm.c | 101 ++++++++-- 5 files changed, 390 insertions(+), 28 deletions(-) create mode 100644 tools/perf/scripts/python/arm-cs-trace-disasm.py -- 2.7.4

6 years, 6 months

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CoreSight June 2018