Re: [RFC PATCH 0/4] perf: Custom contexts

[Frederic Weisbecker]

On Mon, Mar 14, 2011 at 05:43:41PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Mon, Mar 14, 2011 at 08:17:59PM +0100, Frederic Weisbecker escreveu:
> > Some examples:
> > 
> > - Trace lock events inside irqs
> > 
> > 	$ perf record -e irq:irq_handler_entry -e irq:irq_handler_exit \
> > 		-e lock:lock_acquire --starter 0 --stopper 1 --enable-on-starter \
> > 		perf bench sched messaging
> 
> A more compact alternative that uses .. to delimit ranges (start and/or
> stop), like git does for changeset ranges and @ to determine where to
> enable the event:
> 
> perf record -e instructions@irq:irq_handler_entry..irq:irq_handler_exit \
> 	perf bench sched messaging
> 
> event-A at-range event-B to event-C
> 
> open ended ranges being possible as well, i.e. start counting when
> event-B triggers and stop only when the workload finishes, or count from
> workload start till event-C triggers.
>  		
> > 	$ perf script
> > 	
> > 	perf-4300  [000]  2000.209721: irq_handler_entry: irq=40 name=ahci
> >       perf-4300  [000]  2000.209725: lock_acquire: 0xffff880037851c40 &(&host->lock)->rlock
> >       perf-4300  [000]  2000.209731: irq_handler_exit: irq=40 ret=handled
> >       perf-4300  [000]  2000.209821: irq_handler_entry: irq=40 name=ahci
> >       perf-4300  [000]  2000.209823: lock_acquire: 0xffff880037851c40 &(&host->lock)->rlock
> >       perf-4300  [000]  2000.209828: irq_handler_exit: irq=40 ret=handled
> > - Count instructions inside softirqs, outside softirqs and everywhere:
> > 
> > 	$ perf stat -e irq:softirq_entry -e irq:softirq_exit \
> > 		-e instructions --starter 0 --stopper 1 --enable-on-starter \
> > 		-e instructions --starter 1 --stopper 0 \
> > 		-e instructions ./perf bench sched messaging
> 
> $ perf record -e instructions@irq:softirq_entry..irq:softirq_exit \
> 	      -e instructions@irq:softirq_exit..irq:softirq_entry \
> 	      -e instructions \
> 	perf bench sched messaging
> 
> - Arnaldo


Agreed that's nice but may be more as a shortcut than a full replacement?
Otherwise it becomes hard or unreadable to define a filter on a starter. Or
a starter on a starter.
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