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[PATCH v5 0/5] perf cs-etm: Fix synthesizing instruction samples

by Leo Yan

This patch series is to address issues for synthesizing instruction samples, especially when the instruction sample period is small enough, the current logic cannot synthesize multiple instruction samples within one instruction range packet. Patch 0001 is to swap packets for instruction samples, so this allow option '--itrace=iNNN' can work well. Patch 0002 avoids to reset the last branches for every instruction sample; if reset the last branches for every time generating sample, the later samples in the same range packet cannot use the last branches anymore. Patch 0003 is the fixing for handling different instruction periods, especially for small sample period. Patch 0004 is an optimization for copying last branches; it only copies last branches once if the instruction samples share the same last branches. Patch 0005 is a minor fix for unsigned variable comparison to zero. This patch set has been rebased on the latest perf/core branch; and verified on Juno board with below commands: # perf script --itrace=i2 # perf script --itrace=i2il16 # perf inject --itrace=i2il16 -i perf.data -o perf.data.new # perf inject --itrace=i100il16 -i perf.data -o perf.data.new Changes from v4: * Added Mike's review tag for patch 03; * Added Mathieu's review tags for all patches. Changes from v3: * Refactored patch 0001 with new function cs_etm__packet_swap() (Mike); * Refined instruction sample generation flow with single while loop, which completely uses Mike's suggestions (Mike); * Added Mike's review tags for patch 01/02/04/05. Changes from v2: * Added patch 0001 which is to fix swapping packets for instruction samples; * Refined minor commit logs and comments; * Rebased on the latest perf/core branch. Changes from v1: * Rebased patch set on perf/core branch with latest commit 9fec3cd5fa4a ("perf map: Check if the map still has some refcounts on exit"). Leo Yan (5): perf cs-etm: Swap packets for instruction samples perf cs-etm: Continuously record last branch perf cs-etm: Correct synthesizing instruction samples perf cs-etm: Optimize copying last branches perf cs-etm: Fix unsigned variable comparison to zero tools/perf/util/cs-etm.c | 157 +++++++++++++++++++++++++++------------ 1 file changed, 111 insertions(+), 46 deletions(-) -- 2.17.1

5 years, 8 months

[PATCH 13/23] perf cs-etm: Fix unsigned variable comparison to zero

by Arnaldo Carvalho de Melo

From: Leo Yan <leo.yan(a)linaro.org> The variable 'offset' in function cs_etm__sample() is u64 type, it's not appropriate to check it with 'while (offset > 0)'; this patch changes to 'while (offset)'. Signed-off-by: Leo Yan <leo.yan(a)linaro.org> Reviewed-by: Mathieu Poirier <mathieu.poirier(a)linaro.org> Reviewed-by: Mike Leach <mike.leach(a)linaro.org> Cc: Alexander Shishkin <alexander.shishkin(a)linux.intel.com> Cc: Jiri Olsa <jolsa(a)redhat.com> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Namhyung Kim <namhyung(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Robert Walker <robert.walker(a)arm.com> Cc: Suzuki Poulouse <suzuki.poulose(a)arm.com> Cc: coresight ml <coresight(a)lists.linaro.org> Cc: linux-arm-kernel(a)lists.infradead.org Link: http://lore.kernel.org/lkml/20200219021811.20067-6-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo <acme(a)redhat.com> --- tools/perf/util/cs-etm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 87d9943177bc..62d2f9b9ce1b 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -962,7 +962,7 @@ static inline u64 cs_etm__instr_addr(struct cs_etm_queue *etmq, if (packet->isa == CS_ETM_ISA_T32) { u64 addr = packet->start_addr; - while (offset > 0) { + while (offset) { addr += cs_etm__t32_instr_size(etmq, trace_chan_id, addr); offset--; -- 2.21.1

5 years, 8 months

[PATCH 12/23] perf cs-etm: Optimize copying last branches

by Arnaldo Carvalho de Melo

From: Leo Yan <leo.yan(a)linaro.org> If an instruction range packet can generate multiple instruction samples, these samples share the same last branches; it's not necessary to copy the same last branches repeatedly for these samples within the same packet. This patch moves out the last branches copying from function cs_etm__synth_instruction_sample(), and execute it prior to generating instruction samples. Signed-off-by: Leo Yan <leo.yan(a)linaro.org> Reviewed-by: Mathieu Poirier <mathieu.poirier(a)linaro.org> Reviewed-by: Mike Leach <mike.leach(a)linaro.org> Cc: Alexander Shishkin <alexander.shishkin(a)linux.intel.com> Cc: Jiri Olsa <jolsa(a)redhat.com> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Namhyung Kim <namhyung(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Robert Walker <robert.walker(a)arm.com> Cc: Suzuki Poulouse <suzuki.poulose(a)arm.com> Cc: coresight ml <coresight(a)lists.linaro.org> Cc: linux-arm-kernel(a)lists.infradead.org Link: http://lore.kernel.org/lkml/20200219021811.20067-5-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo <acme(a)redhat.com> --- tools/perf/util/cs-etm.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 1ddcc67e13dd..87d9943177bc 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -1151,10 +1151,8 @@ static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq, cs_etm__copy_insn(etmq, tidq->trace_chan_id, tidq->packet, &sample); - if (etm->synth_opts.last_branch) { - cs_etm__copy_last_branch_rb(etmq, tidq); + if (etm->synth_opts.last_branch) sample.branch_stack = tidq->last_branch; - } if (etm->synth_opts.inject) { ret = cs_etm__inject_event(event, &sample, @@ -1431,6 +1429,10 @@ static int cs_etm__sample(struct cs_etm_queue *etmq, u64 offset = etm->instructions_sample_period - instrs_prev; u64 addr; + /* Prepare last branches for instruction sample */ + if (etm->synth_opts.last_branch) + cs_etm__copy_last_branch_rb(etmq, tidq); + while (tidq->period_instructions >= etm->instructions_sample_period) { /* @@ -1508,6 +1510,11 @@ static int cs_etm__flush(struct cs_etm_queue *etmq, if (etmq->etm->synth_opts.last_branch && tidq->prev_packet->sample_type == CS_ETM_RANGE) { + u64 addr; + + /* Prepare last branches for instruction sample */ + cs_etm__copy_last_branch_rb(etmq, tidq); + /* * Generate a last branch event for the branches left in the * circular buffer at the end of the trace. @@ -1515,7 +1522,7 @@ static int cs_etm__flush(struct cs_etm_queue *etmq, * Use the address of the end of the last reported execution * range */ - u64 addr = cs_etm__last_executed_instr(tidq->prev_packet); + addr = cs_etm__last_executed_instr(tidq->prev_packet); err = cs_etm__synth_instruction_sample( etmq, tidq, addr, @@ -1560,11 +1567,16 @@ static int cs_etm__end_block(struct cs_etm_queue *etmq, */ if (etmq->etm->synth_opts.last_branch && tidq->prev_packet->sample_type == CS_ETM_RANGE) { + u64 addr; + + /* Prepare last branches for instruction sample */ + cs_etm__copy_last_branch_rb(etmq, tidq); + /* * Use the address of the end of the last reported execution * range. */ - u64 addr = cs_etm__last_executed_instr(tidq->prev_packet); + addr = cs_etm__last_executed_instr(tidq->prev_packet); err = cs_etm__synth_instruction_sample( etmq, tidq, addr, -- 2.21.1

5 years, 8 months

[PATCH 11/23] perf cs-etm: Correct synthesizing instruction samples

by Arnaldo Carvalho de Melo

From: Leo Yan <leo.yan(a)linaro.org> When 'etm->instructions_sample_period' is less than 'tidq->period_instructions', the function cs_etm__sample() cannot handle this case properly with its logic. Let's see below flow as an example: - If we set itrace option '--itrace=i4', then function cs_etm__sample() has variables with initialized values: tidq->period_instructions = 0 etm->instructions_sample_period = 4 - When the first packet is coming: packet->instr_count = 10; the number of instructions executed in this packet is 10, thus update period_instructions as below: tidq->period_instructions = 0 + 10 = 10 instrs_over = 10 - 4 = 6 offset = 10 - 6 - 1 = 3 tidq->period_instructions = instrs_over = 6 - When the second packet is coming: packet->instr_count = 10; in the second pass, assume 10 instructions in the trace sample again: tidq->period_instructions = 6 + 10 = 16 instrs_over = 16 - 4 = 12 offset = 10 - 12 - 1 = -3 -> the negative value tidq->period_instructions = instrs_over = 12 So after handle these two packets, there have below issues: The first issue is that cs_etm__instr_addr() returns the address within the current trace sample of the instruction related to offset, so the offset is supposed to be always unsigned value. But in fact, function cs_etm__sample() might calculate a negative offset value (in handling the second packet, the offset is -3) and pass to cs_etm__instr_addr() with u64 type with a big positive integer. The second issue is it only synthesizes 2 samples for sample period = 4. In theory, every packet has 10 instructions so the two packets have total 20 instructions, 20 instructions should generate 5 samples (4 x 5 = 20). This is because cs_etm__sample() only calls once cs_etm__synth_instruction_sample() to generate instruction sample per range packet. This patch fixes the logic in function cs_etm__sample(); the basic idea for handling coming packet is: - To synthesize the first instruction sample, it combines the left instructions from the previous packet and the head of the new packet; then generate continuous samples with sample period; - At the tail of the new packet, if it has the rest instructions, these instructions will be left for the sequential sample. Suggested-by: Mike Leach <mike.leach(a)linaro.org> Signed-off-by: Leo Yan <leo.yan(a)linaro.org> Reviewed-by: Mathieu Poirier <mathieu.poirier(a)linaro.org> Reviewed-by: Mike Leach <mike.leach(a)linaro.org> Cc: Alexander Shishkin <alexander.shishkin(a)linux.intel.com> Cc: Jiri Olsa <jolsa(a)redhat.com> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Namhyung Kim <namhyung(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Robert Walker <robert.walker(a)arm.com> Cc: Suzuki Poulouse <suzuki.poulose(a)arm.com> Cc: coresight ml <coresight(a)lists.linaro.org> Cc: linux-arm-kernel(a)lists.infradead.org Link: http://lore.kernel.org/lkml/20200219021811.20067-4-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo <acme(a)redhat.com> --- tools/perf/util/cs-etm.c | 87 ++++++++++++++++++++++++++++++++-------- 1 file changed, 70 insertions(+), 17 deletions(-) diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 2c4156c5ed09..1ddcc67e13dd 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -1358,9 +1358,12 @@ static int cs_etm__sample(struct cs_etm_queue *etmq, struct cs_etm_auxtrace *etm = etmq->etm; int ret; u8 trace_chan_id = tidq->trace_chan_id; - u64 instrs_executed = tidq->packet->instr_count; + u64 instrs_prev; - tidq->period_instructions += instrs_executed; + /* Get instructions remainder from previous packet */ + instrs_prev = tidq->period_instructions; + + tidq->period_instructions += tidq->packet->instr_count; /* * Record a branch when the last instruction in @@ -1378,26 +1381,76 @@ static int cs_etm__sample(struct cs_etm_queue *etmq, * TODO: allow period to be defined in cycles and clock time */ - /* Get number of instructions executed after the sample point */ - u64 instrs_over = tidq->period_instructions - - etm->instructions_sample_period; + /* + * Below diagram demonstrates the instruction samples + * generation flows: + * + * Instrs Instrs Instrs Instrs + * Sample(n) Sample(n+1) Sample(n+2) Sample(n+3) + * | | | | + * V V V V + * -------------------------------------------------- + * ^ ^ + * | | + * Period Period + * instructions(Pi) instructions(Pi') + * + * | | + * \---------------- -----------------/ + * V + * tidq->packet->instr_count + * + * Instrs Sample(n...) are the synthesised samples occurring + * every etm->instructions_sample_period instructions - as + * defined on the perf command line. Sample(n) is being the + * last sample before the current etm packet, n+1 to n+3 + * samples are generated from the current etm packet. + * + * tidq->packet->instr_count represents the number of + * instructions in the current etm packet. + * + * Period instructions (Pi) contains the the number of + * instructions executed after the sample point(n) from the + * previous etm packet. This will always be less than + * etm->instructions_sample_period. + * + * When generate new samples, it combines with two parts + * instructions, one is the tail of the old packet and another + * is the head of the new coming packet, to generate + * sample(n+1); sample(n+2) and sample(n+3) consume the + * instructions with sample period. After sample(n+3), the rest + * instructions will be used by later packet and it is assigned + * to tidq->period_instructions for next round calculation. + */ /* - * Calculate the address of the sampled instruction (-1 as - * sample is reported as though instruction has just been - * executed, but PC has not advanced to next instruction) + * Get the initial offset into the current packet instructions; + * entry conditions ensure that instrs_prev is less than + * etm->instructions_sample_period. */ - u64 offset = (instrs_executed - instrs_over - 1); - u64 addr = cs_etm__instr_addr(etmq, trace_chan_id, - tidq->packet, offset); + u64 offset = etm->instructions_sample_period - instrs_prev; + u64 addr; - ret = cs_etm__synth_instruction_sample( - etmq, tidq, addr, etm->instructions_sample_period); - if (ret) - return ret; + while (tidq->period_instructions >= + etm->instructions_sample_period) { + /* + * Calculate the address of the sampled instruction (-1 + * as sample is reported as though instruction has just + * been executed, but PC has not advanced to next + * instruction) + */ + addr = cs_etm__instr_addr(etmq, trace_chan_id, + tidq->packet, offset - 1); + ret = cs_etm__synth_instruction_sample( + etmq, tidq, addr, + etm->instructions_sample_period); + if (ret) + return ret; - /* Carry remaining instructions into next sample period */ - tidq->period_instructions = instrs_over; + offset += etm->instructions_sample_period; + tidq->period_instructions -= + etm->instructions_sample_period; + } } if (etm->sample_branches) { -- 2.21.1

5 years, 8 months

[PATCH 10/23] perf cs-etm: Continuously record last branch

by Arnaldo Carvalho de Melo

From: Leo Yan <leo.yan(a)linaro.org> Every time synthesize instruction sample, the last branch recording will be reset. This is fine if the instruction period is big enough, for example if use the option '--itrace=i100000', the last branch array is reset for every sample with 100000 instructions per period; before generate the next instruction sample, there has the sufficient packets coming to fill the last branch array. On the other hand, if set a very small period, the packets will be significantly reduced between two continuous instruction samples, thus the last branch array is almost empty for new instruction sample by frequently resetting. To allow the last branches to work properly for any instruction periods, this patch avoids to reset the last branch for every instruction sample and only reset it when flush the trace data. The last branches will be reset only for two cases, one is for trace starting, another case is for discontinuous trace; other cases can keep recording last branches for continuous instruction samples. Signed-off-by: Leo Yan <leo.yan(a)linaro.org> Reviewed-by: Mathieu Poirier <mathieu.poirier(a)linaro.org> Reviewed-by: Mike Leach <mike.leach(a)linaro.org> Cc: Alexander Shishkin <alexander.shishkin(a)linux.intel.com> Cc: Jiri Olsa <jolsa(a)redhat.com> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Namhyung Kim <namhyung(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Robert Walker <robert.walker(a)arm.com> Cc: Suzuki Poulouse <suzuki.poulose(a)arm.com> Cc: coresight ml <coresight(a)lists.linaro.org> Cc: linux-arm-kernel(a)lists.infradead.org Link: http://lore.kernel.org/lkml/20200219021811.20067-3-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo <acme(a)redhat.com> --- tools/perf/util/cs-etm.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 294b09cfb034..2c4156c5ed09 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -1170,9 +1170,6 @@ static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq, "CS ETM Trace: failed to deliver instruction event, error %d\n", ret); - if (etm->synth_opts.last_branch) - cs_etm__reset_last_branch_rb(tidq); - return ret; } @@ -1487,6 +1484,10 @@ static int cs_etm__flush(struct cs_etm_queue *etmq, swap_packet: cs_etm__packet_swap(etm, tidq); + /* Reset last branches after flush the trace */ + if (etm->synth_opts.last_branch) + cs_etm__reset_last_branch_rb(tidq); + return err; } -- 2.21.1

5 years, 8 months

[PATCH 09/23] perf cs-etm: Swap packets for instruction samples

by Arnaldo Carvalho de Melo

From: Leo Yan <leo.yan(a)linaro.org> If use option '--itrace=iNNN' with Arm CoreSight trace data, perf tool fails inject instruction samples; the root cause is the packets are only swapped for branch samples and last branches but not for instruction samples, so the new coming packets cannot be properly handled for only synthesizing instruction samples. To fix this issue, this patch refactors the code with a new function cs_etm__packet_swap() which is used to swap packets and adds the condition for instruction samples. Signed-off-by: Leo Yan <leo.yan(a)linaro.org> Reviewed-by: Mathieu Poirier <mathieu.poirier(a)linaro.org> Reviewed-by: Mike Leach <mike.leach(a)linaro.org> Cc: Alexander Shishkin <alexander.shishkin(a)linux.intel.com> Cc: Jiri Olsa <jolsa(a)redhat.com> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Namhyung Kim <namhyung(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Robert Walker <robert.walker(a)arm.com> Cc: Suzuki Poulouse <suzuki.poulose(a)arm.com> Cc: coresight ml <coresight(a)lists.linaro.org> Cc: linux-arm-kernel(a)lists.infradead.org Link: http://lore.kernel.org/lkml/20200219021811.20067-2-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo <acme(a)redhat.com> --- tools/perf/util/cs-etm.c | 39 +++++++++++++++++++-------------------- 1 file changed, 19 insertions(+), 20 deletions(-) diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index b3b3fe3ea345..294b09cfb034 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -363,6 +363,23 @@ struct cs_etm_packet_queue return NULL; } +static void cs_etm__packet_swap(struct cs_etm_auxtrace *etm, + struct cs_etm_traceid_queue *tidq) +{ + struct cs_etm_packet *tmp; + + if (etm->sample_branches || etm->synth_opts.last_branch || + etm->sample_instructions) { + /* + * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for + * the next incoming packet. + */ + tmp = tidq->packet; + tidq->packet = tidq->prev_packet; + tidq->prev_packet = tmp; + } +} + static void cs_etm__packet_dump(const char *pkt_string) { const char *color = PERF_COLOR_BLUE; @@ -1342,7 +1359,6 @@ static int cs_etm__sample(struct cs_etm_queue *etmq, struct cs_etm_traceid_queue *tidq) { struct cs_etm_auxtrace *etm = etmq->etm; - struct cs_etm_packet *tmp; int ret; u8 trace_chan_id = tidq->trace_chan_id; u64 instrs_executed = tidq->packet->instr_count; @@ -1406,15 +1422,7 @@ static int cs_etm__sample(struct cs_etm_queue *etmq, } } - if (etm->sample_branches || etm->synth_opts.last_branch) { - /* - * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for - * the next incoming packet. - */ - tmp = tidq->packet; - tidq->packet = tidq->prev_packet; - tidq->prev_packet = tmp; - } + cs_etm__packet_swap(etm, tidq); return 0; } @@ -1443,7 +1451,6 @@ 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; /* Handle start tracing packet */ if (tidq->prev_packet->sample_type == CS_ETM_EMPTY) @@ -1478,15 +1485,7 @@ static int cs_etm__flush(struct cs_etm_queue *etmq, } swap_packet: - if (etm->sample_branches || etm->synth_opts.last_branch) { - /* - * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for - * the next incoming packet. - */ - tmp = tidq->packet; - tidq->packet = tidq->prev_packet; - tidq->prev_packet = tmp; - } + cs_etm__packet_swap(etm, tidq); return err; } -- 2.21.1

5 years, 8 months

Cmake compatibility

by subhasish Karmakar

Hi, Do you have Cmake based build or bitbake recipe for OpenCSD project? My project is CMAKE based. I want to integrate OpenCSD with it. Regards, Subhasish

5 years, 8 months

[PATCH v5 0/6] Describe CoreSight topology using sysfs links

by Mike Leach

The connections between CoreSight sources, links and sinks is not obvious without documentation or access to the device tree / ACPI definitions for the platform. This patchset provides sysfs links to enable the user to follow the trace patch from source to sink. Components in the trace path are updated to have a connections sysfs group, which collates all the links for that component. The CTI components which exist aside from the main trace patch, also have an added connections directory showing connections to other CoreSight devices. This patchset applies on top of the recent CTI v10 patchset [1]. Adaptation of an original patchset [2] from Suzuki, reusing 2 patches unchanged with update to 3rd adapt to the new common code for trace path and CTI component links & add a default connections group. Tested on Juno r1, DB410c; kernel 5.6-rc3 [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2020-February/714140.… [2] https://lists.linaro.org/pipermail/coresight/2019-May/002803.html Changes since v4: 1) Rebased for v10 CTI set[1]. 2) Code for adding in the CTI->[other CoreSight] links revised to ensure consistent create / release process. Warn on highly unlikely event that link cannot be made & remove any programmatic association between the components. Changes since v3: 1) Rebased onto 5.6-rc1 kernel with CTI set[1]. Changes since v2: 1) Fixed issues with signature ordering noted by Suzuki. 2) Alterations to main CTI set[1] to overcome issue noted by Matthieu. Changes since v1: 1) Code from original v4 CTI set moved here so that all connections related code in this set. 2) Connections directory mandatory for all CoreSight components and generated as part of the registration process. Mike Leach (3): coresight: Add generic sysfs link creation functions coresight: cti: Add in sysfs links to other coresight devices coresight: docs: Add information about the topology representations Suzuki K Poulose (3): coresight: Pass coresight_device for coresight_release_platform_data coresight: add return value for fixup connections coresight: Expose device connections via sysfs .../trace/coresight/coresight-ect.rst | 5 +- Documentation/trace/coresight/coresight.rst | 85 ++++++++ drivers/hwtracing/coresight/Makefile | 3 +- drivers/hwtracing/coresight/coresight-cti.c | 52 ++++- .../hwtracing/coresight/coresight-platform.c | 2 +- drivers/hwtracing/coresight/coresight-priv.h | 12 +- drivers/hwtracing/coresight/coresight-sysfs.c | 204 ++++++++++++++++++ drivers/hwtracing/coresight/coresight.c | 75 ++++--- include/linux/coresight.h | 22 ++ 9 files changed, 428 insertions(+), 32 deletions(-) create mode 100644 drivers/hwtracing/coresight/coresight-sysfs.c -- 2.17.1

5 years, 8 months

perf record cs_etm: data lost

by Andrea Brunato

Good afternoon, When using perf to record a simple benchmark I see the following warning: $ perf record --per-thread -e cs_etm/sinkid=0xa6509eae/u ~/afdo/coremark/coremark/coremark.exe 0x3415 0x3415 0x66 0 7 1 2000 > run2.log [ perf record: Woken up 6 times to write data ] Warning: AUX data lost 6 times out of 6! [ perf record: Captured and wrote 0.378 MB perf.data ] This is on DB845c (https://www.96boards.org/product/rb3-platform/), kernel 5.5.0-rc7. It looks like perf is losing data and the reported perf.data file is very tiny, given that the application runs for several seconds. Does anybody have any idea about what it may be causing this? I've tried adding --mmap-pages=32K,64K to the command for increasing the buffer size, but it's not actually solving the problem Thanks, Andrea IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.

5 years, 8 months

gdb: instructions and functions recording on ARM processors using CoreSight ETM

by Zied Guermazi

Good afternoon, I would like to announce the breakthrough in extending gdb with non intrusive instructions and functions tracing on ARM processors using Coresight ETM traces, as described in previous mails. the source code is made public in the git repository https://github.com/gzied/binutils-gdb/ in the branch gdb_arm_coresight. this implementation was compiled and tested on an STM32MP1 (ARMv7 Architecture) board running "Linux arm 5.3.10-armv7-lpae-x15" distribution where the device tree was modified to declare CoreSight components. to build the software >checkout the software from the branch gdb_arm_coresight > cd .. >mkdir build >cd build > ../binutils-gdb/configure --with-arm-cs >make after a successful build gdb will be available in the folder build/gdb to run the software build the software you would like to debug with debugging info (-g flag) >gcc -g software.c -o software start debugging your software >gdb software set a breakpoint at main (gdb) b main (gdb) run set a breakpoint in a location after the code you would like to trace (gdb) b my_function set your etm sink, sinks can be found by listing the folder /sys/bus/event_source/devices/cs_etm/sinks/. use a sink that is capable of storing the traces on chip (etf, etb ...) (gdb) set record btrace etm sink tmc_etf0 start recording etm traces (gdb) record btrace etm continue the execution of the program (gdb) c wait until the breakpoint is hit, analyse and display the traces - on assembly level (gdb) record instruction-history - on c level (gdb) record function-call-history /ilc you can increase the number of instructions displayed by using (gdb) set record instruction-history-size size (gdb) set record function-call-history-size size the work is still in an early stage and needs to be improved, extended and stabilized. your feedback and contributions are welcome Kind Regards Zied Guermazi

5 years, 9 months

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