This patch seris adds support for sample flags so can facilitate perf
to print sample flags for branch instruction.
The branch instructions also include exception taken and return
related instructions, so the first patch is used to generate branch
sample for exception packets; and the second patch is to track the
exception number.
The patch 0003 is to set branch instruction flags in packet, this
patch has the core code in this series to set flags according to the
decoding element type, and also based on the elements including
instruction type, subtype and condition flag to help making decision
to set flags value.
The patch 0004 is to support sample flags by copying the flags value
from packet structure to sample structure, and it includes two fixing
up for TRACE_ON and exception packets.
The patch series is based on OpenCSD v0.10.0 and Rob's patch 'perf:
Support for Arm A32/T32 instruction sets in CoreSight trace' also is
prerequisite to support A32/T32 ISAs.
The patches can be applied on the acme core branch [1] and tested on
Juno board with below commands for A64 and A32/T32 building:
# perf script -F,-time,+flags,+ip,+sym,+addr -k vmlinux
Leo Yan (4):
perf cs-etm: Generate branch sample for exception packet
perf cs-etm: Track exception number
perf cs-etm: Set branch instruction flags in packet
perf cs-etm: Add support sample flags
tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 237 +++++++++++++++++++++++-
tools/perf/util/cs-etm-decoder/cs-etm-decoder.h | 11 +-
tools/perf/util/cs-etm.c | 44 ++++-
3 files changed, 277 insertions(+), 15 deletions(-)
--
2.7.4
Hi,
We are trying to us the Open CSD for decoding a onchip trace in our ETB.
The trace was enabled and is captured in the ETB.
We read the trace back and dumped it into a text file.
I am attaching it.
How can I use the CSD tool to decode it?
Thanks
Ajith
Hi,
I'm taking this back to the linaro coresight list so we can get the OpenCSD
library versioning sorted out.
The first patch splits the OpenCSD feature check into two parts. The
original check is left as is - this just checks for the presence of an
OpenCSD library. A new check (libopencsd-numinstr) is added that checks
for the new OpenCSD (>0.9.0) that has the num_instr_range member in the
ocsd_generic_trace_elem struct. This feature is then used to set a flag
used in cs-etm-decoder.c to select which versions of 2 functions are used
to get the instruction count / last instruction size of each instruction
block - if the flag is not set, then the previous assumptions of a 4 byte
instruction size are used. It was suggested that OpenCSD should export a
version header - I agree this is a good idea, but this will require a new
release of the library, so we would miss support for the instruction sizes
when OpenCSD 0.9.{0,1,2} is installed - hence why I've kept the version
check using the presence of num_instr_range.
The second patch adds support for finding the T32 instruction counts when
the OpenCSD library doesn't report the instruction counts. As this
involves iterating through the block of instructions and examining each
instruction, there is a significant peformance hit (about 5x slower than
using the OpenCSD library to report the instruction counts), so I'm not
sure this patch should go into upstream.
Regards
Rob
Robert Walker (2):
perf: Support for Arm A32/T32 instruction sets in CoreSight trace
perf: Full support for Arm T32 instructions with older version of
OpenCSD
tools/build/Makefile.feature | 3 +-
tools/build/feature/Makefile | 4 +
tools/build/feature/test-libopencsd-numinstr.c | 15 ++++
tools/perf/Makefile.config | 3 +
tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 106 ++++++++++++++++++++++++
tools/perf/util/cs-etm-decoder/cs-etm-decoder.h | 10 +++
tools/perf/util/cs-etm.c | 71 +++++++---------
7 files changed, 171 insertions(+), 41 deletions(-)
create mode 100644 tools/build/feature/test-libopencsd-numinstr.c
--
2.7.4
This patchset adds more information about the final instuction in the
Instruction Range generic packet.
i) A flag is set if the last instruction is conditional [last_instr_cond].
ii) for A32/T32 ISA, the instruction subtype will be set to 'Implied Return'
[OCSD_S_INSTR_V7_IMPLIED_RET] if it is one of the instructions:
mov pc,lr
bx r14
pop {...,pc}
ldr pc,[sp], #offset
These are used by the CPU return predictor and in general by compilers
when a return is required.
The patchset also removes the uint32_t casts in the version #define
OCSD_VER_NUM to enable correct use with pre-processor.
updates for v2:
i) Instruction matching for implied return tightened to focus correctly on
specific instructions
ii) Typos in help / printed text corrected.
Mike Leach (4):
opencsd: Generic output packet - add additional instruction info
opencsd: Typo Fixes.
opencsd: docs: Update documents for new generic packet field
opencsd: Update README etc for version 0.10.0
README.md | 6 ++-
decoder/docs/doxygen_config.dox | 2 +-
decoder/docs/prog_guide/prog_guide_generic_pkts.md | 3 +-
decoder/include/common/trc_gen_elem.h | 1 +
.../include/opencsd/etmv4/trc_pkt_decode_etmv4i.h | 2 +
decoder/include/opencsd/ocsd_if_types.h | 1 +
decoder/include/opencsd/ocsd_if_version.h | 8 ++--
decoder/include/opencsd/trc_gen_elem_types.h | 1 +
decoder/source/etmv3/trc_pkt_decode_etmv3.cpp | 1 +
decoder/source/etmv4/trc_pkt_decode_etmv4i.cpp | 29 ++++++--------
decoder/source/i_dec/trc_i_decode.cpp | 1 +
decoder/source/i_dec/trc_idec_arminst.cpp | 46 +++++++++++-----------
decoder/source/ocsd_dcd_tree.cpp | 1 -
decoder/source/ptm/trc_pkt_decode_ptm.cpp | 2 +
decoder/source/trc_gen_elem.cpp | 7 +++-
decoder/tests/source/trc_pkt_lister.cpp | 2 +-
16 files changed, 61 insertions(+), 52 deletions(-)
--
2.14.2
Greetings,
I'm trying to find an ARM server dedicated for high-computing and
parallelism,
that also supports Coresight.
The Cavium ThunderX2 fits perfectly for the performance requirements, but
i'm not quite sure Coresight is supported. This isn't documented anywhere,
so i thought it's best to ask this here.
Is Coresight supported on ThunderX2?
Thank you,
Mike.
The perf sample data contains flags to indicate the hardware trace data
is belonging to which type branch instruction, thus this can be used to
print out the human readable string. Arm CoreSight ETM sample data is
missed to set flags and it is always set to zeros, this results in perf
tool skips to print string for instruction types.
Arm CoreSight ETM supports different kind instruction of A64, A32 and
T32; as the first step, this patch is to set sample flags for A64
instructions.
The brief idea for implementation is describe as below:
- For element with OCSD_GEN_TRC_ELEM_TRACE_ON type, it is taken as trace
beginning packet; for element with OCSD_GEN_TRC_ELEM_NO_SYNC or
OCSD_GEN_TRC_ELEM_EO_TRACE, these two kinds elements are used to set
for trace end;
- For instruction range packet, mainly base on three factors to decide
the branch instruction types:
elem->last_i_type
elem->last_i_subtype
elem->last_instr_cond
If the instruction is immediate branch but without link and return
flag, we consider it as function internal branch; in fact the
immediate branch also can be used to invoke the function entry,
usually this is only used in assembly code to directly call a symbol
and don't expect to return back; after reviewing kernel normal
functions and user space programs, both of them are very seldom to use
immediate branch for function call. On the other hand, if we want to
decide the immediate branch is for function branch jumping or for
function calling, we need to rely on the start address of next packet
and check the symbol offset for the start address, this will
introduce much complexity in the implementation. So for this version
we simply consider immediate branch as function internal branch.
If the instruction is immediate branch with link, it's instruction
'BL' and which is used for function call.
If the instruction is indirect branch without link, this is
corresponding to instruction 'BR', this instruction usually is used
for dynamic link lib with below usage; so we think it's a return
instruction.
0000000000000680 <.plt>:
680: a9bf7bf0 stp x16, x30, [sp, #-16]!
684: 90000090 adrp x16, 10000 <__FRAME_END__+0xf630>
688: f947fe11 ldr x17, [x16, #4088]
68c: 913fe210 add x16, x16, #0xff8
690: d61f0220 br x17
If the instruction is indirect branch with link, e.g BLR, we think
it's a function call.
For function return, ARMv8 introduces a dedicated instruction 'ret',
which has flag of OCSD_S_INSTR_V8_RET.
- For exception packets, this patch divides into three types:
The first type of exception is caused by external logics like bus,
interrupt controller, debug module or PE reset or halt; this is
corresponding to flags "bcyi" which defined in doc perf-script.txt;
The second type is for system call, this is set as "bcs" by following
definition in the doc;
The third type is for CPU trap, data and instruction prefetch abort,
alignment abort; usually these exceptions are synchronous for CPU, so
set them as "bci" type.
This part is not very certain that this patch has set right flags for
them, the reason is the instruction trace decoding flags is original
from Intel PT and it's briefly defined in the document:
tools/perf/Documentation/perf-script.txt. But there have no more
detailed information to explain these flags and their corresponding
instructions.
This patch set exception related flags based on the literal meaning
which described in the doc, and should refine according to reviewing.
Cc: Mathieu Poirier <mathieu.poirier(a)linaro.org>
Cc: Mike Leach <mike.leach(a)linaro.org>
Cc: Robert Walker <robert.walker(a)arm.com>
Cc: Al Grant <Al.Grant(a)arm.com>
Cc: Andi Kleen <andi(a)firstfloor.org>
Cc: Adrian Hunter <adrian.hunter(a)intel.com>
Cc: Arnaldo Carvalho de Melo <acme(a)redhat.com>
Signed-off-by: Leo Yan <leo.yan(a)linaro.org>
---
tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 158 ++++++++++++++++++++++++
tools/perf/util/cs-etm-decoder/cs-etm-decoder.h | 1 +
tools/perf/util/cs-etm.c | 4 +-
3 files changed, 161 insertions(+), 2 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 938def6..b7cb962 100644
--- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
@@ -347,6 +347,162 @@ cs_etm_decoder__buffer_trace_on(struct cs_etm_decoder *decoder,
CS_ETM_TRACE_ON);
}
+static void cs_etm_decoder__set_sample_flags(
+ const void *context,
+ const ocsd_generic_trace_elem *elem)
+{
+ struct cs_etm_decoder *decoder = (struct cs_etm_decoder *) context;
+ struct cs_etm_packet *packet;
+ static u32 exc_num;
+
+ packet = &decoder->packet_buffer[decoder->tail];
+
+ switch (elem->elem_type) {
+ case OCSD_GEN_TRC_ELEM_TRACE_ON:
+ packet->flags = PERF_IP_FLAG_BRANCH |
+ PERF_IP_FLAG_TRACE_BEGIN;
+ break;
+
+ case OCSD_GEN_TRC_ELEM_NO_SYNC:
+ case OCSD_GEN_TRC_ELEM_EO_TRACE:
+ packet->flags = PERF_IP_FLAG_BRANCH |
+ PERF_IP_FLAG_TRACE_END;
+ break;
+
+ case OCSD_GEN_TRC_ELEM_INSTR_RANGE:
+ /*
+ * Immediate branch instruction without neither link nor
+ * return flag, it's normal branch instruction within
+ * the function.
+ */
+ if (elem->last_i_type == OCSD_INSTR_BR &&
+ elem->last_i_subtype == OCSD_S_INSTR_NONE) {
+ packet->flags = PERF_IP_FLAG_BRANCH;
+
+ if (elem->last_instr_cond)
+ packet->flags |= PERF_IP_FLAG_CONDITIONAL;
+ }
+
+ /*
+ * Immediate branch instruction with link (e.g. BL), this is
+ * branch instruction for function call.
+ */
+ if (elem->last_i_type == OCSD_INSTR_BR &&
+ elem->last_i_subtype == OCSD_S_INSTR_BR_LINK)
+ packet->flags = PERF_IP_FLAG_BRANCH |
+ PERF_IP_FLAG_CALL;
+
+ /*
+ * Indirect branch instruction without link (e.g. BR), usually
+ * this is used for function return, especially for functions
+ * within dynamic link lib.
+ */
+ if (elem->last_i_type == OCSD_INSTR_BR_INDIRECT &&
+ elem->last_i_subtype == OCSD_S_INSTR_NONE)
+ packet->flags = PERF_IP_FLAG_BRANCH |
+ PERF_IP_FLAG_RETURN;
+
+ /*
+ * Indirect branch instruction with link (e.g. BLR), this is
+ * branch instruction for function call.
+ */
+ if (elem->last_i_type == OCSD_INSTR_BR_INDIRECT &&
+ elem->last_i_subtype == OCSD_S_INSTR_BR_LINK)
+ packet->flags = PERF_IP_FLAG_BRANCH |
+ PERF_IP_FLAG_CALL;
+
+ /* Return instruction for function return. */
+ if (elem->last_i_type == OCSD_INSTR_BR_INDIRECT &&
+ elem->last_i_subtype == OCSD_S_INSTR_V8_RET)
+ packet->flags = PERF_IP_FLAG_BRANCH |
+ PERF_IP_FLAG_RETURN;
+
+ break;
+
+ case OCSD_GEN_TRC_ELEM_EXCEPTION:
+
+#define OCSD_EXC_RESET 0
+#define OCSD_EXC_DEBUG_HALT 1
+#define OCSD_EXC_CALL 2
+#define OCSD_EXC_TRAP 3
+#define OCSD_EXC_SYSTEM_ERROR 4
+#define OCSD_EXC_INST_DEBUG 6
+#define OCSD_EXC_DATA_DEBUG 7
+#define OCSD_EXC_ALIGNMENT 10
+#define OCSD_EXC_INST_FAULT 11
+#define OCSD_EXC_DATA_FAULT 12
+#define OCSD_EXC_IRQ 14
+#define OCSD_EXC_FIQ 15
+
+ /*
+ * Exception number is saved and can be used for return
+ * instruction analysis.
+ */
+ exc_num = elem->exception_number;
+
+ /*
+ * The exceptions are triggered by external signals
+ * from bus, interrupt controller, debug module,
+ * PE reset or halt.
+ */
+ if (exc_num == OCSD_EXC_RESET ||
+ exc_num == OCSD_EXC_DEBUG_HALT ||
+ exc_num == OCSD_EXC_SYSTEM_ERROR ||
+ exc_num == OCSD_EXC_INST_DEBUG ||
+ exc_num == OCSD_EXC_DATA_DEBUG ||
+ exc_num == OCSD_EXC_IRQ ||
+ exc_num == OCSD_EXC_FIQ)
+ packet->flags = PERF_IP_FLAG_BRANCH |
+ PERF_IP_FLAG_CALL |
+ PERF_IP_FLAG_ASYNC |
+ PERF_IP_FLAG_INTERRUPT;
+
+ /* The exception is for system call. */
+ if (exc_num == OCSD_EXC_CALL)
+ packet->flags = PERF_IP_FLAG_BRANCH |
+ PERF_IP_FLAG_CALL |
+ PERF_IP_FLAG_SYSCALLRET;
+
+ /*
+ * The exception is introduced by trap, instruction &
+ * data fault or alignment errors.
+ */
+ if (exc_num == OCSD_EXC_TRAP ||
+ exc_num == OCSD_EXC_ALIGNMENT ||
+ exc_num == OCSD_EXC_INST_FAULT ||
+ exc_num == OCSD_EXC_DATA_FAULT)
+ packet->flags = PERF_IP_FLAG_BRANCH |
+ PERF_IP_FLAG_CALL |
+ PERF_IP_FLAG_INTERRUPT;
+
+ break;
+
+ case OCSD_GEN_TRC_ELEM_EXCEPTION_RET:
+ if (exc_num == OCSD_EXC_CALL)
+ packet->flags = PERF_IP_FLAG_BRANCH |
+ PERF_IP_FLAG_RETURN |
+ PERF_IP_FLAG_SYSCALLRET;
+ else
+ packet->flags = PERF_IP_FLAG_BRANCH |
+ PERF_IP_FLAG_RETURN |
+ PERF_IP_FLAG_INTERRUPT;
+ exc_num = -1;
+ break;
+
+ case OCSD_GEN_TRC_ELEM_UNKNOWN:
+ case OCSD_GEN_TRC_ELEM_PE_CONTEXT:
+ case OCSD_GEN_TRC_ELEM_ADDR_NACC:
+ case OCSD_GEN_TRC_ELEM_TIMESTAMP:
+ case OCSD_GEN_TRC_ELEM_CYCLE_COUNT:
+ case OCSD_GEN_TRC_ELEM_ADDR_UNKNOWN:
+ case OCSD_GEN_TRC_ELEM_EVENT:
+ case OCSD_GEN_TRC_ELEM_SWTRACE:
+ case OCSD_GEN_TRC_ELEM_CUSTOM:
+ default:
+ break;
+ }
+}
+
static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer(
const void *context,
const ocsd_trc_index_t indx __maybe_unused,
@@ -390,6 +546,8 @@ static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer(
break;
}
+ cs_etm_decoder__set_sample_flags(context, elem);
+
return resp;
}
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 612b575..9d5f65a 100644
--- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
@@ -36,6 +36,7 @@ struct cs_etm_packet {
u8 exc;
u8 exc_ret;
int cpu;
+ u32 flags;
};
struct cs_etm_queue;
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 3b37d66..bf66eb6 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -663,7 +663,7 @@ static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq,
sample.stream_id = etmq->etm->instructions_id;
sample.period = period;
sample.cpu = etmq->packet->cpu;
- sample.flags = 0;
+ sample.flags = etmq->prev_packet->flags;
sample.insn_len = 1;
sample.cpumode = event->header.misc;
@@ -719,7 +719,7 @@ static int cs_etm__synth_branch_sample(struct cs_etm_queue *etmq)
sample.stream_id = etmq->etm->branches_id;
sample.period = 1;
sample.cpu = etmq->packet->cpu;
- sample.flags = 0;
+ sample.flags = etmq->prev_packet->flags;
sample.cpumode = PERF_RECORD_MISC_USER;
/*
--
2.7.4
-Moves ocsd_if_version.h into include/opencsd and adds to headers used
as part of installation.
-Fixes bug in snapshot reader library used by test programs to handle
'offset' parameter in [dump] sections correctly.
--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK
This patchset adds more information about the final instuction in the
Instruction Range generic packet.
i) A flag is set if the last instruction is conditional [last_instr_cond].
ii) for A32/T32 ISA, the instruction subtype will be set to 'Implied Return'
[OCSD_S_INSTR_V7_IMPLIED_RET] if it is one of the instructions:
mov pc,lr
bx r14
pop {...,pc}
ldr pc,[sp], #offset
These are used by the CPU return predictor and in general by compilers
when a return is required.
The patchset also removes the uint32_t casts in the version #define
OCSD_VER_NUM to enable correct use with pre-processor.
Mike Leach (3):
opencsd: Generic output packet - add additional instruction info
opencsd: docs: Update documents for new generic packet field
opencsd: Update README etc for version 0.10.0
README.md | 6 +++--
decoder/docs/doxygen_config.dox | 2 +-
decoder/docs/prog_guide/prog_guide_generic_pkts.md | 3 ++-
decoder/include/common/trc_gen_elem.h | 1 +
.../include/opencsd/etmv4/trc_pkt_decode_etmv4i.h | 2 ++
decoder/include/opencsd/ocsd_if_types.h | 1 +
decoder/include/opencsd/ocsd_if_version.h | 8 +++---
decoder/include/opencsd/trc_gen_elem_types.h | 1 +
decoder/source/etmv3/trc_pkt_decode_etmv3.cpp | 1 +
decoder/source/etmv4/trc_pkt_decode_etmv4i.cpp | 29 ++++++++++------------
decoder/source/i_dec/trc_i_decode.cpp | 1 +
decoder/source/i_dec/trc_idec_arminst.cpp | 16 ++++++++++++
decoder/source/ocsd_dcd_tree.cpp | 1 -
decoder/source/ptm/trc_pkt_decode_ptm.cpp | 2 ++
decoder/source/trc_gen_elem.cpp | 5 +++-
15 files changed, 53 insertions(+), 26 deletions(-)
--
2.14.2
Hi Mathieu, Mike,
[ + CoreSight list ]
When reviewed Andi's patch 'tools, perf, script: Add --call-trace and
--call-ret-trace' [1], I found after applying this patch with
CoreSight, perf fails to output two fields: one is missing to output
the sample flags (e.g. 'call', 'return', 'jmp', etc) [2], another
missing is failed to output the symbols [3]. The cause for the issues
is CoreSight doesn't set sample flags and simply set it to zero [4].
If I understand correctly (Mathieu also mentioned to me at connect),
I think before you guys have awared for this. So want to check if you
have existed fixing for this in case I am doing duplicate works at
here? :) Or there have some discussion and known issues so cannot
enable sample flags before?
I did some investigation for these, CoreSight can set partial sample
flags for A64 branch instructions with packet infos:
- ocsd_generic_trace_elem::last_i_type can be used to check if the
instruction is immediate branch instruction or indirect branch
instruction;
- ocsd_generic_trace_elem::last_i_subtype can be used to distinguish
if it's link branch instruction (OCSD_S_INSTR_BR_LINK), if it's link
branch instruction then this means this branch insturction is for
function call;
if it's return branch instruction (OCSD_S_INSTR_V8_RET), then it's
return instruction;
Otherwise (OCSD_S_INSTR_NONE), it's a simple branch instruction
within the function.
But there still have several things are not clear for me:
- How can we distinguish the exception is for system call, or
interrupt. The reason is we can see Intel-pt set sample flags for
different values for different exception types:
PERF_IP_FLAG_INTERRUPT
PERF_IP_FLAG_SYSCALLRET
I think we might can use ocsd_generic_trace_elem::exception_number
to distinguish the different exception types, but I don't find any
doc to clear define for this value.
- I don't know if there have any info or hints in CoreSight packet can
be used to indicate the branch is conditional branch or not. For
Intel-pt, it can set the conditional branch instruction with flag:
PERF_IP_FLAG_CONDITIONAL.
- I understand it's low priority to support A32 and T32 instructions,
but just note here I also don't have no idea for this part.
Could you give some suggestion and guidance for this? Thanks in
advance.
Thanks,
Leo Yan
[1] https://lore.kernel.org/patchwork/patch/987916/
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/too…
[3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/too…
[4] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/too…
