Re: [PATCH 6/8] perf tools: Add new comm infrastructure

From: Namhyung Kim
Date: Mon Oct 28 2013 - 01:38:55 EST


Hi David,

On Fri, 25 Oct 2013 12:19:07 -0600, David Ahern wrote:
> On 10/25/13 12:12 PM, Frederic Weisbecker wrote:
>> Oh I see. It's possible that my massive conversion to use the comm
>> accessor got blind at some point and left over a few things. I
>> remember that I only lightly tested that new comm infrastructure. I
>> mean I tested a lot of "perf report -s foo,bar" combinations for
>> performance comparisons but I haven't tested the perf script and all
>> the other perf tools.
>>
>> I'll rebase these patches and test that wider before resending.
>
> specifically, I see stuff like perf forking ls and comm still shows as
> perf even though there is COMM record with the rename to ls. I believe
> the test case was something like:
>
> perf sched record -- ls
> perf script

Hmm.. did you try my latest v5 patchset? I couldn't reproduce the case
at least for the command lines above.

$ perf script
perf 24810 [007] 1546517.815809: sched:sched_stat_runtime: comm=perf pid=24810 ru
perf 24810 [007] 1546517.815909: sched:sched_wakeup: comm=perf pid=24811 prio=120
swapper 0 [008] 1546517.815913: sched:sched_switch: prev_comm=swapper/8 prev_pid
perf 24810 [007] 1546517.815953: sched:sched_stat_runtime: comm=perf pid=24810 ru
perf 24810 [007] 1546517.815957: sched:sched_switch: prev_comm=perf prev_pid=2481
perf 24811 [008] 1546517.815992: sched:sched_wakeup: comm=migration/8 pid=48 prio
perf 24811 [008] 1546517.815993: sched:sched_stat_runtime: comm=perf pid=24811 ru
perf 24811 [008] 1546517.815993: sched:sched_switch: prev_comm=perf prev_pid=2481
migration/8 48 [008] 1546517.815996: sched:sched_migrate_task: comm=perf pid=24811 pr
migration/8 48 [008] 1546517.816000: sched:sched_switch: prev_comm=migration/8 prev_p
swapper 0 [009] 1546517.816002: sched:sched_switch: prev_comm=swapper/9 prev_pid
ls 24811 [009] 1546517.816808: sched:sched_stat_runtime: comm=ls pid=24811 runt


Here, the process 24811 has only 3 samples before COMM event

$ perf report -D | grep 24811 | grep -v MMAP | head
0 0 0x629b0 [0x38]: PERF_RECORD_COMM: perf:24811
8 1546517815992058 0x65f50 [0x68]: PERF_RECORD_SAMPLE(IP, 1): 24811/24811: 0xffffffff81091512 period: 1 addr: 0
... thread: perf:24811
8 1546517815993189 0x65fb8 [0x70]: PERF_RECORD_SAMPLE(IP, 1): 24811/24811: 0xffffffff81099d25 period: 83314 addr: 0
... thread: perf:24811
8 1546517815993975 0x66028 [0x80]: PERF_RECORD_SAMPLE(IP, 1): 24811/24811: 0xffffffff81659d60 period: 1 addr: 0
... thread: perf:24811
9 1546517816224342 0x66378 [0x38]: PERF_RECORD_COMM: ls:24811
9 1546517816808637 0x667f0 [0x70]: PERF_RECORD_SAMPLE(IP, 1): 24811/24811: 0xffffffff81099d25 period: 810663 addr: 0
... thread: ls:24811

$ perf version
perf version 3.11.ge9eb20


Thanks,
Namhyung
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