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Date: Fri, 15 Sep 2023 17:14:09 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Ravi Bangoria <ravi.bangoria@....com>,
Yang Jihong <yangjihong1@...wei.com>, peterz@...radead.org,
mingo@...hat.com, mark.rutland@....com,
alexander.shishkin@...ux.intel.com, jolsa@...nel.org,
irogers@...gle.com, adrian.hunter@...el.com,
kan.liang@...ux.intel.com, james.clark@....com,
tmricht@...ux.ibm.com, ak@...ux.intel.com,
anshuman.khandual@....com, linux-kernel@...r.kernel.org,
linux-perf-users@...r.kernel.org
Subject: Re: [PATCH v8 0/6] perf record: Track sideband events for all CPUs
when tracing selected CPUs
Hello,
On Tue, Sep 12, 2023 at 1:32 PM Arnaldo Carvalho de Melo
<acme@...nel.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@....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.
$ sudo ./perf test -v 17
17: Setup struct perf_event_attr :
--- start ---
test child forked, pid 1616372
Using CPUID GenuineIntel-6-8C-1
running './tests/attr/test-record-branch-filter-k'
running './tests/attr/test-record-period'
running './tests/attr/test-record-graph-default'
test limitation '!aarch64'
excluded architecture list ['aarch64']
running './tests/attr/test-record-branch-filter-any'
running './tests/attr/test-record-data'
running './tests/attr/test-stat-detailed-1'
running './tests/attr/test-record-branch-filter-hv'
running './tests/attr/test-record-graph-fp'
test limitation '!aarch64'
excluded architecture list ['aarch64']
running './tests/attr/test-record-basic'
running './tests/attr/test-record-group2'
running './tests/attr/test-stat-detailed-3'
running './tests/attr/test-record-branch-any'
running './tests/attr/test-record-branch-filter-ind_call'
running './tests/attr/test-stat-detailed-2'
running './tests/attr/test-record-group1'
running './tests/attr/test-record-count'
running './tests/attr/test-record-no-samples'
running './tests/attr/test-record-graph-dwarf'
running './tests/attr/test-record-spe-period'
test limitation 'aarch64'
skipped [x86_64] './tests/attr/test-record-spe-period'
running './tests/attr/test-record-graph-fp-aarch64'
test limitation 'aarch64'
skipped [x86_64] './tests/attr/test-record-graph-fp-aarch64'
running './tests/attr/test-record-freq'
running './tests/attr/test-record-pfm-period'
running './tests/attr/test-record-no-buffering'
running './tests/attr/test-record-no-inherit'
running './tests/attr/test-record-branch-filter-any_ret'
running './tests/attr/test-record-raw'
running './tests/attr/test-record-dummy-C0'
expected read_format=4, got 20
FAILED './tests/attr/test-record-dummy-C0' - match failure
test child finished with -1
---- end ----
Setup struct perf_event_attr: FAILED!
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