Snapshot mode for regular events

Posted Jul 8, 2015 14:54 UTC (Wed) by mmechri (subscriber, #95694)
Parent article: Adding Processor Trace support to Linux

Does perf support something similar to the snapshot mode described in this article, but for regular perf events?

Example: Suppose I am debugging the same latency glitch as described in this article. I am suspecting L1d misses to be the cause. When the glitch occurs, I would like to tell perf to dump the L1d misses. Is it something feasible with perf?

Snapshot mode for regular events

Posted Jul 9, 2015 16:42 UTC (Thu) by andikleen2 (guest, #52506) [Link]

snapshot mode is currently only supported for aux tracing, so no we can't yet dump other events on the signal.
The other events are always continuously dumped, as the perf record needs to keep track of all the MMAP events and COMM to be able to decode later.
I agree it would be a useful feature though.