> Gentle ping
OK,
thanks!
Honza
>
> > On 20 Jan 2026, at 3:45 PM, Prachi Godbole <[email protected]> wrote:
> >
> > <0001-ipa-reorder-for-locality-Adjust-bootstrap-lto-locali.patch>
> >
> > I’ve updated the patch as per discussion and lowered the default value.
> > Attaching the new version here.
> >
> > This patch turns off -fipa-reorder-for-locality for -fprofile-generate
> > because
> > it's not required and contributes to the bloated time taken by bootstrap.
> > It
> > also reduces the default partition size by half; the increased number of
> > partitions speeds up LTRANS phase.
> >
> > Bootstrapped and tested on aarch64-none-linux-gnu. OK for mainline?
> >
> > Signed-off-by: Prachi Godbole <[email protected]>
> >
> > config/ChangeLog:
> >
> > * bootstrap-lto-locality.mk (STAGE2_CFLAGS): Add param
> > lto-max-locality-partition.
> > (STAGE3_CFLAGS): Ditto.
> > (STAGEprofile_CFLAGS): Remove -fipa-reorder-for-locality.
> > (STAGEtrain_CFLAGS): Ditto.
> >
> > gcc/Changelog:
> >
> > * params.opt: Change default param value.
> >
> >
> >
> >> On 16 Jan 2026, at 6:09 PM, Prachi Godbole <[email protected]> wrote:
> >>
> >>
> >>
> >>> On 16 Jan 2026, at 5:56 PM, Jan Hubicka <[email protected]> wrote:
> >>>
> >>> External email: Use caution opening links or attachments
> >>>
> >>>
> >>>> Thank you Honza for the review
> >>>>
> >>>>
> >>>> The default value was tuned according to the target applications - large
> >>>> applications that benefit from the higher size. This results in majority
> >>>> of the target applications not needing param adjustment. I see ~5-10%
> >>>> improvement for the current default over a lower value.
> >>>>
> >>>> The adjustment I made here was for additional build time improvement
> >>>> specifically for GCC bootstrap with the intention that the target
> >>>> applications can use the pass without needing it.
> >>>
> >>> I see that 5-10% improvement is quite important for the specific
> >>> use-case. It is kind of unfortunate that we need to tune the parameter
> >>> so high. Is it something that can be fixed by better code placement
> >>> across adjacent partitions (which can be acomplished by tp_first_run
> >>> machinery and also your new numbered textsubsections) or is it really
> >>> about late IPA optimizations (such as register alloation) being important
> >>> and ltrans partition being in a way?
> >>>
> >>> I think we should go with reasonable defaults (which does not bow up
> >>> build times) in GCC, so perhaps param should be lowered by default to
> >>> what we need for bootstrap and have the target app to bump it up in its
> >>> config.
> >>>
> >>> Hozna
> >>
> >> Unfortunately, it’s about IPA optimizations and specifically how many
> >> clones are created - having too low a default will blow up the code size.
> >> Following your suggestion, I’ll try with a lowered default - meeting
> >> halfway between current default and the param here so that we don’t blow
> >> up build time and also the apps don’t require too much adjustment. I’ll be
> >> back with that patch
> >>
> >> Thanks,
> >> Prachi
> >>
> >
>
