Messages in this thread | | | Subject | Re: [PATCH v8 0/6] perf record: Track sideband events for all CPUs when tracing selected CPUs | From | Yang Jihong <> | Date | Sat, 16 Sep 2023 17:23:57 +0800 |
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Hello,
On 2023/9/16 8:14, Namhyung Kim wrote: > Hello, > > On Tue, Sep 12, 2023 at 1:32 PM Arnaldo Carvalho de Melo > <acme@kernel.org> wrote: >> >> Em Tue, Sep 12, 2023 at 02:41:56PM +0530, Ravi Bangoria escreveu: >>> On 04-Sep-23 8:03 AM, Yang Jihong wrote: >>>> User space tasks can migrate between CPUs, track sideband events for all >>>> CPUs. >>>> >>>> The specific scenarios are as follows: >>>> >>>> CPU0 CPU1 >>>> perf record -C 0 start >>>> taskA starts to be created and executed >>>> -> PERF_RECORD_COMM and PERF_RECORD_MMAP >>>> events only deliver to CPU1 >>>> ...... >>>> | >>>> migrate to CPU0 >>>> | >>>> Running on CPU0 <----------/ >>>> ... >>>> >>>> perf record -C 0 stop >>>> >>>> Now perf samples the PC of taskA. However, perf does not record the >>>> PERF_RECORD_COMM and PERF_RECORD_COMM events of taskA. >>>> Therefore, the comm and symbols of taskA cannot be parsed. >>>> >>>> The sys_perf_event_open invoked is as follows: >>>> >>>> # perf --debug verbose=3 record -e cpu-clock -C 1 true >>>> <SNIP> >>>> Opening: cpu-clock >>>> ------------------------------------------------------------ >>>> perf_event_attr: >>>> type 1 (PERF_TYPE_SOFTWARE) >>>> size 136 >>>> config 0 (PERF_COUNT_SW_CPU_CLOCK) >>>> { sample_period, sample_freq } 4000 >>>> sample_type IP|TID|TIME|CPU|PERIOD|IDENTIFIER >>>> read_format ID|LOST >>>> disabled 1 >>>> inherit 1 >>>> freq 1 >>>> sample_id_all 1 >>>> exclude_guest 1 >>>> ------------------------------------------------------------ >>>> sys_perf_event_open: pid -1 cpu 1 group_fd -1 flags 0x8 = 5 >>>> Opening: dummy:u >>>> ------------------------------------------------------------ >>>> perf_event_attr: >>>> type 1 (PERF_TYPE_SOFTWARE) >>>> size 136 >>>> config 0x9 (PERF_COUNT_SW_DUMMY) >>>> { sample_period, sample_freq } 1 >>>> sample_type IP|TID|TIME|CPU|IDENTIFIER >>>> read_format ID|LOST >>>> inherit 1 >>>> exclude_kernel 1 >>>> exclude_hv 1 >>>> mmap 1 >>>> comm 1 >>>> task 1 >>>> sample_id_all 1 >>>> exclude_guest 1 >>>> mmap2 1 >>>> comm_exec 1 >>>> ksymbol 1 >>>> bpf_event 1 >>>> ------------------------------------------------------------ >>>> sys_perf_event_open: pid -1 cpu 0 group_fd -1 flags 0x8 = 6 >>>> sys_perf_event_open: pid -1 cpu 1 group_fd -1 flags 0x8 = 7 >>>> sys_perf_event_open: pid -1 cpu 2 group_fd -1 flags 0x8 = 9 >>>> sys_perf_event_open: pid -1 cpu 3 group_fd -1 flags 0x8 = 10 >>>> sys_perf_event_open: pid -1 cpu 4 group_fd -1 flags 0x8 = 11 >>>> sys_perf_event_open: pid -1 cpu 5 group_fd -1 flags 0x8 = 12 >>>> sys_perf_event_open: pid -1 cpu 6 group_fd -1 flags 0x8 = 13 >>>> sys_perf_event_open: pid -1 cpu 7 group_fd -1 flags 0x8 = 14 >>>> <SNIP> >>>> >>>> Changes since_v7: >>>> - The condition for requiring system_wide sideband is changed to >>>> "as long as a non-dummy event exists" (patch4). >>>> - Modify the corresponding test case to record only dummy event (patch6). >>>> - Thanks to tested-by tag from Ravi, but because the solution is modified, >>>> the tested-by tag of Ravi is not added to this version. >>> >>> I've re-tested v8 with my simple test. >>> >>> Tested-by: Ravi Bangoria <ravi.bangoria@amd.com> >> >> >> Thanks, applied to the csets that were still sitting in an umpublished >> perf-tools-next local branch, soon public. > > Now I'm seeing a perf test failure on perf-tools-next.
Uh.. the kernel I was using before didn't support PERF_FORMAT_LOST, so forget about supporting PERF_FORMAT_LOST. I've updated the kernel and retested it.
The link to the fixed patch is as follows: https://lore.kernel.org/all/20230916091641.776031-1-yangjihong1@huawei.com/
Thanks, Yang
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