kernel/tools/perf/Documentation/perf-record.txt, branch linux-4.17.y

perf record: Throttle user defined frequencies to the maximum allowed

2018-03-05T12:58:44Z

# perf record -F 200000 sleep 1 warning: Maximum frequency rate (15,000 Hz) exceeded, throttling from 200,000 Hz to 15,000 Hz. The limit can be raised via /proc/sys/kernel/perf_event_max_sample_rate. The kernel will lower it when perf's interrupts take too long. Use --strict-freq to disable this throttling, refusing to record. [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.019 MB perf.data (15 samples) ] # perf evlist -v cycles:ppp: size: 112, { sample_period, sample_freq }: 15000, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 For those wanting that it fails if the desired frequency can't be used: # perf record --strict-freq -F 200000 sleep 1 error: Maximum frequency rate (15,000 Hz) exceeded. Please use -F freq option with a lower value or consider tweaking /proc/sys/kernel/perf_event_max_sample_rate. # Suggested-by: Ingo Molnar Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: https://lkml.kernel.org/n/tip-oyebruc44nlja499nqkr1nzn@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf record: Allow asking for the maximum allowed sample rate

2018-03-05T12:58:43Z

Add the handy '-F max' shortcut to reading and using the kernel.perf_event_max_sample_rate value as the user supplied sampling frequency: # perf record -F max sleep 1 info: Using a maximum frequency rate of 15,000 Hz [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.019 MB perf.data (14 samples) ] # sysctl kernel.perf_event_max_sample_rate kernel.perf_event_max_sample_rate = 15000 # perf evlist -v cycles:ppp: size: 112, { sample_period, sample_freq }: 15000, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 # perf record -F 10 sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.019 MB perf.data (4 samples) ] # perf evlist -v cycles:ppp: size: 112, { sample_period, sample_freq }: 10, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 # Suggested-by: Ingo Molnar Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: https://lkml.kernel.org/n/tip-4y0tiuws62c64gp4cf0hme0m@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf cgroup: Simplify arguments when tracking multiple events

2018-02-22T13:02:27Z

When using -G with one cgroup and -e with multiple events, only the first event gets the correct cgroup setting, all events from the second onwards will track system-wide events. If the user wants to track multiple events for a specific cgroup, the user must give parameters like the following: $ perf stat -e e1 -e e2 -e e3 -G test,test,test This patch simplify this case, just type one cgroup: $ perf stat -e e1 -e e2 -e e3 -G test $ mkdir -p /sys/fs/cgroup/perf_event/empty_cgroup $ perf stat -e cycles -e cache-misses -a -I 1000 -G empty_cgroup Before: 1.001007226 cycles empty_cgroup 1.001007226 7,506 cache-misses After: 1.000834097 cycles empty_cgroup 1.000834097 cache-misses empty_cgroup Signed-off-by: weiping zhang Acked-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20180129154805.GA6284@localhost.didichuxing.com [ Improved the doc text a bit, providing an example for cgroup + system wide counting ] Signed-off-by: Arnaldo Carvalho de Melo

perf record: Record the first and last sample time in the header

2018-01-08T14:20:56Z

In the default 'perf record' configuration, all samples are processed, to create the HEADER_BUILD_ID table. So it's very easy to get the first/last samples and save the time to perf file header via the function write_sample_time(). Later, at post processing time, perf report/script will fetch the time from perf file header. Committer testing: # perf record -a sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 2.099 MB perf.data (1101 samples) ] [root@jouet home]# perf report --header | grep "time of " # time of first sample : 22947.909226 # time of last sample : 22948.910704 # # perf report -D | grep PERF_RECORD_SAMPLE\( 0 22947909226101 0x20bb68 [0x30]: PERF_RECORD_SAMPLE(IP, 0x4001): 0/0: 0xffffffffa21b1af3 period: 1 addr: 0 0 22947909229928 0x20bb98 [0x30]: PERF_RECORD_SAMPLE(IP, 0x4001): 0/0: 0xffffffffa200d204 period: 1 addr: 0 3 22948910397351 0x219360 [0x30]: PERF_RECORD_SAMPLE(IP, 0x4001): 28251/28251: 0xffffffffa22071d8 period: 169518 addr: 0 0 22948910652380 0x20f120 [0x30]: PERF_RECORD_SAMPLE(IP, 0x4001): 0/0: 0xffffffffa2856816 period: 198807 addr: 0 2 22948910704034 0x2172d0 [0x30]: PERF_RECORD_SAMPLE(IP, 0x4001): 0/0: 0xffffffffa2856816 period: 88111 addr: 0 # Changelog: v7: Just update the patch description according to Arnaldo's suggestion. v6: Currently '--buildid-all' is not enabled at default. So the walking on all samples is the default operation. There is no big overhead to calculate the timestamp boundary in process_sample_event handler once we already go through all samples. So the timestamp boundary calculation is enabled by default when '--buildid-all' is not enabled. While if '--buildid-all' is enabled, we creates a new option "--timestamp-boundary" for user to decide if it enables the timestamp boundary calculation. v5: There is an issue that the sample walking can only work when '--buildid-all' is not enabled. So we need to let the walking be able to work even if '--buildid-all' is enabled and let the processing skips the dso hit marking for this case. At first, I want to provide a new option "--record-time-boundaries". While after consideration, I think a new option is not very necessary. v3: Remove the definitions of first_sample_time and last_sample_time from struct record and directly save them in perf_evlist. Signed-off-by: Jin Yao Acked-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Andi Kleen Cc: Kan Liang Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1512738826-2628-3-git-send-email-yao.jin@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo

Merge branch 'perf/urgent' into perf/core, to pick up fixes

2017-10-20T09:02:05Z

Signed-off-by: Ingo Molnar

perf record: Fix documentation for a inexistent option '-l'

2017-10-17T12:05:36Z

'perf record' had a '-l' option that meant "scale counter values" a very long time ago, but it currently belongs to 'perf stat' as '-c'. So remove it. I found this problem in the below case. $ perf record -e cycles -l sleep 3 Error: unknown switch `l Signed-off-by: Taeung Song Cc: Jiri Olsa Cc: Namhyung Kim Link: http://lkml.kernel.org/r/1507907412-19813-1-git-send-email-treeze.taeung@gmail.com Signed-off-by: Arnaldo Carvalho de Melo

perf record: Support direct --user-regs arguments

2017-09-13T12:49:14Z

USER_REGS can currently only collected implicitely with call graph recording. Sometimes it is useful to see them separately, and filter them. Add a new --user-regs option to record that is similar to --intr-regs, but acts on user regs. Signed-off-by: Andi Kleen Cc: Jiri Olsa Link: http://lkml.kernel.org/r/20170905170029.19722-1-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Support new sample type for physical address

2017-09-01T17:46:00Z

Support new sample type PERF_SAMPLE_PHYS_ADDR for physical address. Add new option --phys-data to record sample physical address. Signed-off-by: Kan Liang Tested-by: Jiri Olsa Acked-by: Stephane Eranian Cc: Andi Kleen Cc: Madhavan Srinivasan Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1504026672-7304-2-git-send-email-kan.liang@intel.com [ Added missing printing in evsel.c patch sent by Jiri Olsa ] Signed-off-by: Arnaldo Carvalho de Melo

perf record: Create a new option save_type in --branch-filter

2017-07-19T02:14:39Z

The option indicates the kernel to save branch type during sampling. One example: perf record -g --branch-filter any,save_type Signed-off-by: Yao Jin Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Andi Kleen Cc: Kan Liang Cc: Michael Ellerman Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1500379995-6449-4-git-send-email-yao.jin@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix spelling mistakes

2017-05-04T12:59:53Z

Mostly in the documentation. Signed-off-by: Kim Phillips Cc: Alexander Shishkin Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20170503131350.cebeecd8bd0f2968417626ab@arm.com [ Fix spelling of "parameter" in one of the spell-checked lines ] Signed-off-by: Arnaldo Carvalho de Melo