Messages in this thread | | | Date | Fri, 31 Jul 2020 19:20:06 +0200 | From | peterz@infradea ... | Subject | Re: [PATCH 0/6] perf tools: Add wallclock time conversion support |
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On Thu, Jul 30, 2020 at 07:21:54PM -0600, David Ahern wrote: > On 7/30/20 4:14 PM, peterz@infradead.org wrote: > > On Thu, Jul 30, 2020 at 11:39:44PM +0200, Jiri Olsa wrote: > > > >> The patchset is adding the ability to display TOD/wallclock timestamp > >> in 'perf script' output and in 'perf data convert --to-ctf' subcommand, > >> so the converted CTF data contain TOD/wallclock timestamps. > > > > But why? Wallclock is a horrible piece of crap. Why would you want to do > > this? > > > > Same reason I brought this up 9+ years ago: userspace lives on > time-of-day, and troubleshooting is based on correlating timestamps from > multiple sources. To correlate a perf event to syslog or an application > log, we need time-of-day.
You need a sync'ed CLOCK_MONOTONIC for that, CLOCK_REALTIME 'aka' wallclock is a trainwreck, you don't ever want that.
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