Messages in this thread | | | Subject | Re: [RFC PATCH 2/5] perf jevents: add support for arch recommended events | From | John Garry <> | Date | Fri, 8 Dec 2017 15:42:10 +0000 |
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On 08/12/2017 12:29, Jiri Olsa wrote: > On Wed, Dec 06, 2017 at 03:20:14PM +0000, John Garry wrote: >> On 06/12/2017 13:36, Jiri Olsa wrote: >>> On Wed, Dec 06, 2017 at 12:13:16AM +0800, John Garry wrote: >>>> For some architectures (like arm64), there are architecture- >>>> defined recommended events. Vendors may not be obliged to >>>> follow the recommendation and may implement their own pmu >>>> event for a specific event code. >>>> >>>> This patch adds support for parsing events from arch-defined >>>> recommended JSONs, and then fixing up vendor events when >>>> they have implemented these events as recommended. >>> >>> in the previous patch you added the vendor support, so >>> you have arch|vendor|platform key for the event list >>> and perf have the most current/local event list >>> >>> why would you need to fix it? if there's new event list, >>> the table gets updated, perf is rebuilt.. I'm clearly >>> missing something ;-) >> >> The 2 patches are quite separate. In the first patch, I just added support >> for the vendor subdirectory. >> >> So this patch is not related to rebuilding when adding a new event list or >> dependency checking. >> >> Here we are trying to allow the vendor to just specify that an event is >> supported as standard in their platform, without duplicating all the >> standard event fields in their JSON. When processing the vendor JSONs, the >> jevents tool can figure which events are standard and create the proper >> event entries in the pmu events table, referencing the architecture JSON. >
Hi jirka,
> I think we should keep this simple and mangle this with some pointer logic > > now you have arch/vendor/platform directory structure..
I'm glad that there seems to be no objection to this, as I feel that this was a problem.
why don't > you add events for every such directory? I understand there will > be duplications, but we already have them for other archs and it's > not big deal:
The amount of duplication was the concern. As mentioned earlier, it would be anticipated that every vendor would implement these events as recommended, so a copy for every platform from every vendor. We're looking for a way to avoid this.
Actually having a scalable JSON standard format for pmu events, which allows us to define common events per architecture / vendor and reference them per platform JSON could be useful.
Here we're dealing with trade-off between duplication (simplicity) vs complexity (or over-engineering).
> > [jolsa@krava perf]$ grep -r L2_RQSTS.DEMAND_DATA_RD_MISS pmu-events/arch/* > pmu-events/arch/x86/broadwell/cache.json: "EventName": "L2_RQSTS.DEMAND_DATA_RD_MISS", > pmu-events/arch/x86/haswell/cache.json: "EventName": "L2_RQSTS.DEMAND_DATA_RD_MISS", > pmu-events/arch/x86/broadwellde/cache.json: "EventName": "L2_RQSTS.DEMAND_DATA_RD_MISS", > pmu-events/arch/x86/haswellx/cache.json: "EventName": "L2_RQSTS.DEMAND_DATA_RD_MISS", > pmu-events/arch/x86/skylake/cache.json: "EventName": "L2_RQSTS.DEMAND_DATA_RD_MISS", > pmu-events/arch/x86/skylakex/cache.json: "EventName": "L2_RQSTS.DEMAND_DATA_RD_MISS", > pmu-events/arch/x86/broadwellx/cache.json: "EventName": "L2_RQSTS.DEMAND_DATA_RD_MISS", > > thanks, > jirka
Cheers, John
> > . >
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