Messages in this thread | | | Date | Sat, 9 Dec 2017 08:31:04 +0100 | From | Jiri Olsa <> | Subject | Re: [RFC PATCH 2/5] perf jevents: add support for arch recommended events |
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On Fri, Dec 08, 2017 at 03:42:10PM +0000, John Garry wrote: > 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
sry for confusion, of course it should have been '.. and NOT mangle..' ;-)
> > > > 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).
understood, but as I said we already are ok with duplicates, if it's reasonable size as is for x86 now.. how much amount are we talking about for arm?
jirka
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