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From: Sam James <sam@gentoo.org>
To: Richard Biener <richard.guenther@gmail.com>
Cc: Eugene Rozenfeld <Eugene.Rozenfeld@microsoft.com>,
	gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] Collect both user and kernel events for autofdo tests and autoprofiledbootstrap
Date: Fri, 30 Jun 2023 09:59:09 +0100	[thread overview]
Message-ID: <87v8f51g0h.fsf@gentoo.org> (raw)
In-Reply-To: <CAFiYyc3V1QXShpObSqMaBn3h+YyR9icGS0Ks0s+pUsSSKs6ZOQ@mail.gmail.com>


Richard Biener via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

> On Fri, Jun 30, 2023 at 7:28 AM Eugene Rozenfeld via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
>>
>> When we collect just user events for autofdo with lbr we get some events where branch
>> sources are kernel addresses and branch targets are user addresses. Without kernel MMAP
>> events create_gcov can't make sense of kernel addresses. Currently create_gcov fails if
>> it can't map at least 95% of events. We sometimes get below this threshold with just
>> user events. The change is to collect both user events and kernel events.
>
> Does this require elevated privileges?  Can we instead "fix" create_gcov here?

Right, requiring privileges for this is going to be a no-go for a lot of
builders. In a distro context, for example, it means we can't consider
autofdo at all.

  reply	other threads:[~2023-06-30  9:00 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-30  5:27 Eugene Rozenfeld
2023-06-30  8:51 ` Richard Biener
2023-06-30  8:59   ` Sam James [this message]
2023-06-30 21:44     ` [EXTERNAL] " Eugene Rozenfeld
2023-06-30 22:05       ` Eugene Rozenfeld
2023-07-03  7:46         ` Richard Biener
2023-07-05 21:15           ` Eugene Rozenfeld
2023-07-06  6:23             ` Richard Biener

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