Re: [PATCH 4/4] perf tools: Add perf trace

[Frederic Weisbecker <fweisbec@gmail.com>]

On Mon, Aug 17, 2009 at 04:40:07PM +0200, Ingo Molnar wrote:
> 
> * Frederic Weisbecker <fweisbec@gmail.com> wrote:
> 
> > This adds perf trace into the set of perf tools. It is written to 
> > fetch the tracepoints samples from perf events and display them, 
> > according to the events informations given by the debugfs files 
> > through the util/trace* tools.
> > 
> > It is a rough first shot and doesn't yet handle the cpu, 
> > timestamps fields and some other things.
> > 
> > Example:
> > 
> > perf record -f -e workqueue:workqueue_execution:record -F 1 -a
> > perf trace
> > 
> >        kblockd/0-236   [000]     0.000000: workqueue_execution: thread=:236 func=cfq_kick_queue+0x0
> >      kondemand/0-360   [000]     0.000000: workqueue_execution: thread=:360 func=do_dbs_timer+0x0
> >      kondemand/0-360   [000]     0.000000: workqueue_execution: thread=:360 func=do_dbs_timer+0x0
> >      kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
> >      kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
> >      kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
> >      kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
> >      kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
> >      kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
> >      kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
> >      kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
> >      kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
> >      kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
> >      kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
> >      kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
> >      kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
> 
> Nice!
> 
> > Todo:
> > 
> > - A lot of things!
> 
> heh :-)
> 
> To help this move forward i've put the patches into 
> tip:perfcounters/tracing. We might still rebase that branch, should 
> it become necessary, before merging it into perfcounters/core - but 
> it should give a first glimpse to people who want to try this.
> 
> A first bugreport:
> 
> took me some time to figure out that i need to pass in -R to create 
> a trace.info. I think we want to share the namespace anyway - 
> there's no real difference between perf.data and trace.info - both 
> contain trace records.



trace.info only contains the events descriptions and other ftrace things:

- formats, ftrace printk strings, ...

I plan to integrate that into perf.trace so that we have only one file
to move to perform offline analysis.

Concerning the -R thing (or ::record suffix), indeed I have yet to
warn the user from perf trace about that. Todo listed!

> 
> once i added -R i ran into this problem:
> 
> # perf record -R -f -e workqueue:workqueue_execution:record -F 1 -a
> ^C
> [ perf record: Captured and wrote 0.250 MB perf.data (~10928 samples) ]
> 
> aldebaran:/home/mingo/linux/linux/tools/perf> perf trace
>   Fatal: bad op token )


Oh!
Hmm, also I forgot to explain a detail, there is a little bug in ftrace
syscalls formats which reports the format is too big when a syscall takes
no parameter. It needs a trivial fix, I'll send it soon.

Anyway, that made me a very similar Fatal thing but not exactly the same.
Could you send me your config? May be you have tracepoint/ftrace plugins
I haven't built (well I should build all of them actually).


> version = 0.5
> 
> Some missing patch?



Soon :)


> 	Ingo
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