IMO PGO should really stay opt-in, not opt-out, given the performance impact.
On Thu, Aug 23, 2018 at 1:28 AM Richard Purdie < [email protected]> wrote: > On Wed, 2018-08-22 at 18:44 -0700, Andre McCurdy wrote: > > On Thu, Aug 16, 2018 at 9:48 PM, Anuj Mittal <[email protected]> > > wrote: > > > On 08/17/2018 03:31 AM, Andre McCurdy wrote: > > > > On Wed, Aug 15, 2018 at 11:26 PM, Anuj Mittal <anuj.mittal@intel. > > > > com> wrote: > > > > Is it important to re-create the profile data during every build > > > > or > > > > would we get most of the same benefits from using reference data > > > > which > > > > is generated offline? > > > > > > We should get the same benefit using the data generated offline as > > > long > > > as the source code/configure options/flags are same I believe. I > > > have > > > only tried with data generate offline using the same build > > > configuration > > > though. > > > > As an additional data point, python do_compile now takes approx 18 > > minutes on my laptop. A single qemu-i386 thread loading one CPU core > > at 100%, with nothing else being scheduled in parallel for most of > > that time. > > > > If we can get most of the benefits of pgo with a pre-generated data > > file then that might still be something to explore. > > I've also noticed the increased build times. I'd love to see if we > could create an sstate object which would contain the pgo data and > which didn't depend on the usual compiler/toolchain pieces, only the > do_patch stage checksum. In theory, the same sstate object should be > reusable between target/native/nativesdk too as long as we had the same > python patchset (which I know we don't for native). > > Anyone fancy such a challenge? We should probably have a bug open for > this at least... > > Cheers, > > Richard > > -- > _______________________________________________ > Openembedded-core mailing list > [email protected] > http://lists.openembedded.org/mailman/listinfo/openembedded-core > -- Christopher Larson kergoth at gmail dot com Founder - BitBake, OpenEmbedded, OpenZaurus Senior Software Engineer, Mentor Graphics
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