[prev in list] [next in list] [prev in thread] [next in thread]
List: cfe-dev
Subject: Re: [cfe-dev] Status of IR vs. frontend PGO (fprofile-generate vs fprofile-instr-generate)
From: Alex Lorenz via cfe-dev <cfe-dev () lists ! llvm ! org>
Date: 2021-06-15 23:26:10
Message-ID: 7348CB85-8EB6-4A4A-9424-04E4F5AA9487 () apple ! com
[Download RAW message or body]
[Attachment #2 (multipart/alternative)]
> On Jun 14, 2021, at 11:25 AM, Reid Kleckner <rnk@google.com> wrote:
>
> Sure, there's no rush to deprecate frontend PGO. In the meantime, would it be OK to \
> update the open source docs to recommend IR PGO over frontend PGO, without making \
> any statement about deprecation? This is mainly to get any new PGO users onto what \
> we think is currently the most well-lit path.
I think that's fine, no objections from us.
>
> On Mon, Jun 14, 2021 at 10:31 AM Alex Lorenz <aleksei_lorenz@apple.com \
> <mailto:aleksei_lorenz@apple.com>> wrote: Bumping up this thread. Based on the \
> initial investigation, I think we can switch to the IR PGO instead of the frontend \
> PGO and so you'll be able to proceed with this deprecation of the frontend PGO. We \
> would like to request some additional time to do a full investigation and prepare \
> for the transition on our end though, ideally we would need about 3 - 6 months to \
> ensure we are prepared for that. Would you be willing to revisit this again in the \
> future once we're ready for that?
> Thanks,
> Alex
>
> > On May 20, 2021, at 9:54 AM, Xinliang David Li <xinliangli@gmail.com \
> > <mailto:xinliangli@gmail.com>> wrote:
> >
> >
> > On Thu, May 20, 2021 at 9:47 AM Reid Kleckner <rnk@google.com \
> > <mailto:rnk@google.com>> wrote: On Wed, May 19, 2021 at 7:48 PM Alex Lorenz \
> > <aleksei_lorenz@apple.com <mailto:aleksei_lorenz@apple.com>> wrote: As far the \
> > possible deprecation of frontend PGO, will that imply that the \
> > `-fprofile-instr-generate / use` options will get removed, or will they still be \
> > supported but will leverage IR PGO instead?
> > That makes sense to me, but we need to untangle the fact that \
> > `-fprofile-instr-generate -fcoverage-mapping` is currently used for coverage, so \
> > a simple alias isn't quite correct.
> > I've always wanted a single, high-level coverage flag, and I always thought it \
> > should be spelled --coverage of -fcoverage, but that seems like it's already \
> > taken by gcov instrumentation. =/ I guess we need to bikeshed a new spelling.
> > Right. -fcoverage-mapping itself does not much so it should probably imply \
> > frontend instrumentation.
> > For migration purposes, if -fcoverage-mapping is used together with \
> > -fprofile-instr-generate (which becomes IR PGO), the latter will be dropped (or a \
> > warning is given). The tricky part is if the user uses the option to specify the \
> > profile path, then we have a problem.
> > David
> >
> > David
> >
>
[Attachment #5 (unknown)]
<html><head><meta http-equiv="Content-Type" content="text/html; \
charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; \
line-break: after-white-space;" class=""><br class=""><div><br class=""><blockquote \
type="cite" class=""><div class="">On Jun 14, 2021, at 11:25 AM, Reid Kleckner <<a \
href="mailto:rnk@google.com" class="">rnk@google.com</a>> wrote:</div><br \
class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">Sure, there's \
no rush to deprecate frontend PGO. In the meantime, would it be OK to update the open \
source docs to recommend IR PGO over frontend PGO, without making any statement about \
deprecation? This is mainly to get any new PGO users onto what we think is currently \
the most well-lit path.</div></div></blockquote><div><br class=""></div><div>I think \
that's fine, no objections from us.</div><br class=""><blockquote type="cite" \
class=""><div class=""><br class=""><div class="gmail_quote"><div dir="ltr" \
class="gmail_attr">On Mon, Jun 14, 2021 at 10:31 AM Alex Lorenz <<a \
href="mailto:aleksei_lorenz@apple.com" target="_blank" \
class="">aleksei_lorenz@apple.com</a>> wrote:<br class=""></div><blockquote \
class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid \
rgb(204,204,204);padding-left:1ex"><div class="">Bumping up this thread. Based on the \
initial investigation, I think we can switch to the IR PGO instead of the frontend \
PGO and so you'll be able to proceed with this deprecation of the frontend PGO. We \
would like to request some additional time to do a full investigation and prepare for \
the transition on our end though, ideally we would need about 3 - 6 months to ensure \
we are prepared for that. Would you be willing to revisit this again in the future \
once we're ready for that?<div class=""><br class=""></div><div \
class="">Thanks,</div><div class="">Alex<br class=""><div class=""><br \
class=""><blockquote type="cite" class=""><div class="">On May 20, 2021, at 9:54 AM, \
Xinliang David Li <<a href="mailto:xinliangli@gmail.com" target="_blank" \
class="">xinliangli@gmail.com</a>> wrote:</div><br class=""><div class=""><div \
dir="ltr" class=""><div dir="ltr" class=""><br class=""></div><br class=""><div \
class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, May 20, 2021 at 9:47 AM \
Reid Kleckner <<a href="mailto:rnk@google.com" target="_blank" \
class="">rnk@google.com</a>> wrote:<br class=""></div><blockquote \
class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid \
rgb(204,204,204);padding-left:1ex"><div dir="ltr" class=""><div dir="ltr" class="">On \
Wed, May 19, 2021 at 7:48 PM Alex Lorenz <<a \
href="mailto:aleksei_lorenz@apple.com" target="_blank" \
class="">aleksei_lorenz@apple.com</a>> wrote:</div><div \
class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px \
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class=""><div \
class=""><div class="">As far the possible deprecation of frontend PGO, will that \
imply that the `-fprofile-instr-generate / use` options will get removed, or will \
they still be supported but will leverage IR PGO \
instead?</div></div></div></blockquote><div class=""><br class=""></div><div \
class="">That makes sense to me, but we need to untangle the fact that \
`-fprofile-instr-generate -fcoverage-mapping` is currently used for coverage, so a \
simple alias isn't quite correct.</div><div class=""><br class=""></div><div \
class="">I've always wanted a single, high-level coverage flag, and I always thought \
it should be spelled --coverage of -fcoverage, but that seems like it's already taken \
by gcov instrumentation. =/ I guess we need to bikeshed a new \
spelling.</div></div></div></blockquote><div class=""><br class=""></div><div \
class="">Right. -fcoverage-mapping itself does not much so it should \
probably imply frontend instrumentation. </div><div class=""><br \
class=""></div><div class="">For migration purposes, if -fcoverage-mapping is used \
together with -fprofile-instr-generate (which becomes IR PGO), the latter will be \
dropped (or a warning is given). The tricky part is if the user uses the option to \
specify the profile path, then we have a problem.</div><div class=""><br \
class=""></div><div class="">David</div><div class=""><br class=""></div><div \
class="">David</div><div class=""> </div></div></div> \
</div></blockquote></div><br class=""></div></div></blockquote></div> \
</div></blockquote></div><br class=""></body></html>
[Attachment #6 (text/plain)]
_______________________________________________
cfe-dev mailing list
cfe-dev@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
[prev in list] [next in list] [prev in thread] [next in thread]
Configure |
About |
News |
Add a list |
Sponsored by KoreLogic