Em Tue, Jan 03, 2017 at 03:32:32PM +0100, Jiri Olsa escreveu: > On Tue, Jan 03, 2017 at 11:20:27AM -0300, Arnaldo Carvalho de Melo wrote: > > Em Tue, Jan 03, 2017 at 09:19:59AM +0100, Jiri Olsa escreveu: > > > It's now possible to specify the threshold size for > > > perf.data like: > > > > > > $ perf record --switch-output=2G ... > > > > > > Once it's reached, the current data are dumped in to the > > > perf.data.<timestamp> file and session does on. > > > > s/does/goes/g > > > > But: > > > > [root@jouet ~]# perf record -F9000 -a --switch-output=1K sleep 5 > > [ perf record: dump data: Woken up 0 times ] > > [ perf record: Dump perf.data.2017010311185502 ] > > [ perf record: dump data: Woken up 1 times ] > > [ perf record: Dump perf.data.2017010311190003 ] > > [ perf record: Woken up 0 times to write data ] > > [ perf record: Dump perf.data.2017010311190020 ] > > [ perf record: Captured and wrote 2.240 MB perf.data.<timestamp> ] > > [root@jouet ~]# ls -larth perf.data.* > > -rw-------. 1 root root 2.3M Jan 3 11:18 perf.data.2017010311181984 > > -rw-------. 1 root root 2.3M Jan 3 11:18 perf.data.2017010311182002 > > -rw-------. 1 root root 2.3M Jan 3 11:18 perf.data.2017010311185502 > > -rw-------. 1 root root 2.3M Jan 3 11:19 perf.data.2017010311190003 > > -rw-------. 1 root root 2.3M Jan 3 11:19 perf.data.2017010311190020 > > [root@jouet ~]# > > > > What is that I am missing? > > hum, I think the size you configured is smaller then the size > of the shared kernel buffer and perf gets woken up by default > only when we cross some level of data that's in.. would need > to check > > also I dont think 1K won't fit even the perf.data > header.. are you trying to break it? ;-)
I'm trying to follow the documentation ;-) Your explanation sounds reasonable, could you get this code to check those constraints and emit a sensible error message? - Arnaldo