Messages in this thread | | | Date | Mon, 13 Mar 2023 20:14:20 +0800 | From | Leo Yan <> | Subject | Re: [BUG] perf: No samples found when using kcore + coresight |
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On Thu, Mar 09, 2023 at 10:06:41AM -0800, Yang Shi wrote:
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> > I reviewed your shared dump, the bad and good perf data both contain the > > dummy event with 'text_poke = 1'. Could you confirm the shared dump in > > your previous email is correct or not? > > Oops, sorry. I pasted the wrong log. The good one looks like > (generated by v5.19): > > # captured on : Wed Mar 8 18:02:58 2023 > # header version : 1 > # data offset : 408 > # data size : 22640 > # feat offset : 23048 > # hostname : fedora > # os release : 6.2.0-coresight+ > # perf version : 5.19.g3d7cb6b04c3f > # arch : aarch64 > # nrcpus online : 128 > # nrcpus avail : 128 > # cpuid : 0x00000000c00fac30 > # total memory : 2108862504 kB > # cmdline : /home/yshi/linux/tools/perf/perf record -e > cs_etm/@tmc_etf63/k --kcore --per-thread -- taskset --cpu-list 1 uname > # event : name = cs_etm/@tmc_etf63/k, , id = { 3832 }, type = 9, size > = 128, { sample_period, sample_freq } = 1, sample_type = > IP|TID|IDENTIFIER, read_format = ID, d > isabled = 1, exclude_user = 1, exclude_hv = 1, enable_on_exec = 1, > sample_id_all = 1, { bp_len, config2 } = 0x12792918 > # event : name = dummy:u, , id = { 3833 }, type = 1, size = 128, > config = 0x9, { sample_period, sample_freq } = 1, sample_type = > IP|TID|IDENTIFIER, read_format = ID, > disabled = 1, exclude_kernel = 1, exclude_hv = 1, mmap = 1, comm = 1, > enable_on_exec = 1, task = 1, sample_id_all = 1, exclude_guest = 1, > mmap2 = 1, comm_exec = 1, > context_switch = 1, ksymbol = 1, bpf_event = 1 > # CPU_TOPOLOGY info available, use -I to display > # NUMA_TOPOLOGY info available, use -I to display > # pmu mappings: armv8_pmuv3_0 = 8, software = 1, arm_cmn_0 = 10, > uprobe = 7, cs_etm = 9, breakpoint = 5, tracepoint = 2, arm_cmn_1 = > 11, kprobe = 6 > # contains AUX area data (e.g. instruction trace) > # CACHE info available, use -I to display > # time of first sample : 18446744073.709551 > # time of last sample : 18446744073.709551 > # sample duration : 0.000 ms > # MEM_TOPOLOGY info available, use -I to display > # missing features: TRACING_DATA CPUDESC BRANCH_STACK GROUP_DESC STAT > CLOCKID DIR_FORMAT COMPRESSED CPU_PMU_CAPS CLOCK_DATA HYBRID_TOPOLOGY > HYBRID_CPU_PMU_CAPS
Thanks for confirmation.
Just a quick summary, here we have two issues:
- With command: perf record -e cs_etm/@tmc_etf63/k --kcore --per-thread \ -- taskset --cpu-list 1 uname",
perf doesn't enable "text poke" attribution.
- With command: perf record -e cs_etm/@tmc_etf63/k --kcore --per-thread \ -- taskset --cpu-list 1 true (in your previous email), or ... perf record --kcore -e cs_etm/@tmc_etf63/k --per-thread \ -- taskset --cpu-list 1 uname (in your shared perf data file),
perf enables "text poke" attribution, in this case, perf fails to decode Arm CoreSight trace data.
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> > Do you mind to share the bad perf.data file with James and me? > > Please check the attachment out. Thanks for looking into this problem.
Thank you for sharing the data. We will look into it.
Leo
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