Re: [RFC v3 01/17] perf kwork: New tool

[Yang Jihong]

Hello Namhyung,

On 2022/7/28 7:33, Namhyung Kim wrote:
> Hello,
>
> On Fri, Jul 8, 2022 at 6:53 PM Yang Jihong <yangjihong1@xxxxxxxxxx> wrote:
> > The perf-kwork tool is used to trace time properties of kernel work
> > (such as irq, softirq, and workqueue), including runtime, latency,
> > and timehist, using the infrastructure in the perf tools to allow
> > tracing extra targets.
> >
> > This is the first commit to reuse perf_record framework code to
> > implement a simple record function, kwork is not supported currently.
> >
> > Test cases:
> >
> >    # perf
> >
> >     usage: perf [--version] [--help] [OPTIONS] COMMAND [ARGS]
> >
> >     The most commonly used perf commands are:
> >    <SNIP>
> >       iostat          Show I/O performance metrics
> >       kallsyms        Searches running kernel for symbols
> >       kmem            Tool to trace/measure kernel memory properties
> >       kvm             Tool to trace/measure kvm guest os
> >       kwork           Tool to trace/measure kernel work properties (latencies)
> >       list            List all symbolic event types
> >       lock            Analyze lock events
> >       mem             Profile memory accesses
> >       record          Run a command and record its profile into perf.data
> >    <SNIP>
> >     See 'perf help COMMAND' for more information on a specific command.
> >
> >    # perf kwork
> >
> >     Usage: perf kwork [<options>] {record}
> >
> >        -D, --dump-raw-trace  dump raw trace in ASCII
> >        -f, --force           don't complain, do it
> >        -k, --kwork <kwork>   list of kwork to profile
> >        -v, --verbose         be more verbose (show symbol address, etc)
> >
> >    # perf kwork record -- sleep 1
> >    [ perf record: Woken up 0 times to write data ]
> >    [ perf record: Captured and wrote 1.787 MB perf.data ]
> >
> > Signed-off-by: Yang Jihong <yangjihong1@xxxxxxxxxx>
> > ---
> [SNIP]
> > +
> > +static int perf_kwork__record(struct perf_kwork *kwork,
> > +                             int argc, const char **argv)
> > +{
> > +       const char **rec_argv;
> > +       unsigned int rec_argc, i, j;
> > +       struct kwork_class *class;
> > +
> > +       const char *const record_args[] = {
> > +               "record",
> > +               "-a",
> > +               "-R",
> > +               "-m", "1024",
> > +               "-c", "1",
>
> Please consider adding '--synth task' to skip costly synthesis
> if you don't need user space symbols.
Yes, we don't need user space symbols now, I'll add this option in next 
fix patch,thanks for your suggestion.

Regards,
Jihong
> .