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Skip idle swapper threads, closes #1732 #1741

Merged
merged 1 commit into from
May 9, 2018
Merged

Skip idle swapper threads, closes #1732 #1741

merged 1 commit into from
May 9, 2018

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bobrik
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@bobrik bobrik commented May 9, 2018

Run queue latency does not make much sense for idle swapper threads.

The same happens in perf sched:

    /*
     * Ignore idle threads:
     */
    if (!strcmp(thread__comm_str(work_list->thread), "swapper"))
        return;
static bool is_idle_sample(struct perf_sample *sample,
	       struct perf_evsel *evsel)
{
    /* pid 0 == swapper == idle task */
    if (strcmp(perf_evsel__name(evsel), "sched:sched_switch") == 0)
        return perf_evsel__intval(evsel, sample, "prev_pid") == 0;

    return sample->pid == 0;
}

@yonghong-song
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Could you also change the places in raw_tracepoint bpf programs in both tools?

@bobrik
Skip idle swapper threads, closes iovisor#1732
86e904e 
Run queue latency does not make much sense for idle `swapper` threads.

The same happens in `perf sched`:

* https://github.com/torvalds/linux/blob/v4.14/tools/perf/builtin-sched.c

```c
    /*
     * Ignore idle threads:
     */
    if (!strcmp(thread__comm_str(work_list->thread), "swapper"))
        return;
```

```c
static bool is_idle_sample(struct perf_sample *sample,
	       struct perf_evsel *evsel)
{
    /* pid 0 == swapper == idle task */
    if (strcmp(perf_evsel__name(evsel), "sched:sched_switch") == 0)
        return perf_evsel__intval(evsel, sample, "prev_pid") == 0;

    return sample->pid == 0;
}
```
@bobrik
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bobrik commented May 9, 2018

@yonghong-song, sure, done.

yonghong-song
yonghong-song approved these changes May 9, 2018
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LGTM. Thanks!

@yonghong-song yonghong-song merged commit 799f46a into iovisor:master May 9, 2018
banh-gao pushed a commit to banh-gao/bcc that referenced this pull request Jun 21, 2018
@bobrik
Skip idle swapper threads, closes iovisor#1732 (iovisor#1741)
9bfc35d 
Run queue latency does not make much sense for idle `swapper` threads.

The same happens in `perf sched`:

* https://github.com/torvalds/linux/blob/v4.14/tools/perf/builtin-sched.c

```c
    /*
     * Ignore idle threads:
     */
    if (!strcmp(thread__comm_str(work_list->thread), "swapper"))
        return;
```

```c
static bool is_idle_sample(struct perf_sample *sample,
	       struct perf_evsel *evsel)
{
    /* pid 0 == swapper == idle task */
    if (strcmp(perf_evsel__name(evsel), "sched:sched_switch") == 0)
        return perf_evsel__intval(evsel, sample, "prev_pid") == 0;

    return sample->pid == 0;
}
```
@xingfeng2510 xingfeng2510 mentioned this pull request Mar 27, 2022
Merged
CrackerCat pushed a commit to CrackerCat/bcc that referenced this pull request Jul 31, 2024
@bobrik
Skip idle swapper threads, closes iovisor#1732 (iovisor#1741)
d8f7fcb 
Run queue latency does not make much sense for idle `swapper` threads.

The same happens in `perf sched`:

* https://github.com/torvalds/linux/blob/v4.14/tools/perf/builtin-sched.c

```c
    /*
     * Ignore idle threads:
     */
    if (!strcmp(thread__comm_str(work_list->thread), "swapper"))
        return;
```

```c
static bool is_idle_sample(struct perf_sample *sample,
	       struct perf_evsel *evsel)
{
    /* pid 0 == swapper == idle task */
    if (strcmp(perf_evsel__name(evsel), "sched:sched_switch") == 0)
        return perf_evsel__intval(evsel, sample, "prev_pid") == 0;

    return sample->pid == 0;
}
```
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@yonghong-song yonghong-song yonghong-song approved these changes

@brendangregg brendangregg Awaiting requested review from brendangregg brendangregg is a code owner

@goldshtn goldshtn Awaiting requested review from goldshtn goldshtn is a code owner

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@bobrik @yonghong-song