Messages in this thread | | | Subject | Re: [PATCH v11 22/28] tracing: Add enable_hist/disable_hist triggers | From | Tom Zanussi <> | Date | Tue, 03 Nov 2015 19:58:26 -0600 |
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On Tue, 2015-11-03 at 17:55 +0900, Namhyung Kim wrote: > On Thu, Oct 22, 2015 at 01:14:26PM -0500, Tom Zanussi wrote: > > Similar to enable_event/disable_event triggers, these triggers enable > > and disable the aggregation of events into maps rather than enabling > > and disabling their writing into the trace buffer. > > > > They can be used to automatically start and stop hist triggers based > > on a matching filter condition. > > > > If there's a paused hist trigger on system:event, the following would > > start it when the filter condition was hit: > > > > # echo enable_hist:system:event [ if filter] > event/trigger > > > > And the following would disable a running system:event hist trigger: > > > > # echo disable_hist:system:event [ if filter] > event/trigger > > What about named hist triggers? Maybe worth adding > "enable/disable_hist_name" too? >
enable_disable_hist should work fine with both named and unnamed hist triggers. As an example, the below sets a couple each of both named and unnamed triggers and enables and disables them using enable/disable_hist. Running this I got the expected output i.e. there were events captured in both named and unnamed histograms:
echo 'hist:name=foo:keys=skbaddr.hex:vals=len:pause if len < 0' > /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger echo 'hist:name=foo:keys=skbaddr.hex:vals=len:pause if len > 256' > /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger echo 'hist:keys=skbaddr.hex:vals=len:pause if len == 256' > /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger echo 'hist:keys=skbaddr.hex:vals=len:pause' > /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
echo 'enable_hist:net:netif_receive_skb if filename==/usr/bin/wget' > /sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger echo 'disable_hist:net:netif_receive_skb if comm==wget' > /sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger
Thanks,
Tom
> Thanks, > Namhyung > > > > > > See Documentation/trace/events.txt for real examples. > > > > Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> > > Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
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