Messages in this thread | | | Subject | Re: s390 perf events JSONs query | From | John Garry <> | Date | Fri, 20 Apr 2018 14:53:27 +0100 |
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On 20/04/2018 14:25, Thomas-Mich Richter wrote: > On 04/20/2018 12:51 PM, John Garry wrote: >> Hi Hendrik, Thomas, >> >> I noticed that in 4.17-rc1 support was included for s390 perf pmu-events. I also notice that the JSONs contain many common (identical actually) events between different chips for this arch. >> >> Support was added for factoring out common arch events in https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/tools/perf/pmu-events?h=next-20180420&id=e9d32c1bf0cd7a98358ec4aa1625bf2b3459b9ac >> >> ARM64 chips use this feature. I am not familiar with the s390 arch, but do you think you could also use this feature? >> >> Thanks, >> John >> > > I have just played with this feature. I was caught off by this error message: > > [root@s35lp76 pmu-events]# ./jevents s390 arch /tmp/xxx 100000 > d 0 4096 s390 arch/s390 > d 1 4096 cf_z14 arch/s390/cf_z14 > f 2 1338 basic.json arch/s390/cf_z14/basic.json > .... > jevents: Ignoring file arch/s390/archevent.json <---- confusing error message
Let me check if this can be silenced.
> > jevents: Processing mapfile arch/s390/mapfile.csv > [root@s35lp76 pmu-events]# > > I started debugging, until I realized this file is still processed..... > (Just a side remark). > > Anyway the features is nice, but it does not save anything in the resulting > pmu-events.c file, correct? The events defined in the common archevent.json > files are just copied into the structures of a specific machine. >
Yes, the resulting derived pmu-events.c should be the same. In fact, if there was naming inconsistencies in JSONs previously, they should now be gone.
> The feature saves time and space when you create the machine specific json > files because it allows you to refer to a common event by name. Cool! > > On s390 we do not create the json files manually, but have some scripts to > create them based on s390 type/model hardware specific input files.
Right, I would say that this is mostly useful when the JSONs are created manually, which was the case in the ARM world, but not x86. I didn't know about s390.
> > @Hendirk, > we could rework our internal tool chain to emit the new "ArchStdEvent" > keyword for common events, but in the end we do not save anything in the > resulting pmu-events.c file. And it requires considerable rework to > support it. > Given that, I would put it very low priority on your todo list, comments? >
Cheers, John
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