From: Thomas Rodgers <trodgers@redhat.com>
To: Jonathan Wakely <jwakely@redhat.com>
Cc: Mike Crowe <mac@mcrowe.com>, "libstdc++" <libstdc++@gcc.gnu.org>,
gcc Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH v2] libstdc++: Do not use pthread_mutex_clocklock with ThreadSanitizer
Date: Mon, 15 May 2023 12:58:58 -0700 [thread overview]
Message-ID: <CAMmuTO9X2ixt=xvDHHsZiEQTV3-OGC0v4jttrqjMy0DbJySqDQ@mail.gmail.com> (raw)
In-Reply-To: <CACb0b4n6MiTz2iV5Ef9HoupLdub65_A8MbY_1dmg+7sLKOOKCQ@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 1737 bytes --]
On Thu, May 11, 2023 at 1:52 PM Jonathan Wakely <jwakely@redhat.com> wrote:
> On Thu, 11 May 2023 at 13:42, Jonathan Wakely <jwakely@redhat.com> wrote:
>
>>
>>
>> On Thu, 11 May 2023 at 13:19, Mike Crowe <mac@mcrowe.com> wrote:
>>
>>> However, ...
>>>
>>> > > diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
>>> > > index 89e7f5f5f45..e2700b05ec3 100644
>>> > > --- a/libstdc++-v3/acinclude.m4
>>> > > +++ b/libstdc++-v3/acinclude.m4
>>> > > @@ -4284,7 +4284,7 @@
>>> AC_DEFUN([GLIBCXX_CHECK_PTHREAD_COND_CLOCKWAIT], [
>>> > > [glibcxx_cv_PTHREAD_COND_CLOCKWAIT=no])
>>> > > ])
>>> > > if test $glibcxx_cv_PTHREAD_COND_CLOCKWAIT = yes; then
>>> > > - AC_DEFINE(_GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT, 1, [Define if
>>> > > pthread_cond_clockwait is available in <pthread.h>.])
>>> > > + AC_DEFINE(_GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT,
>>> (_GLIBCXX_TSAN==0),
>>> > > [Define if pthread_cond_clockwait is available in <pthread.h>.])
>>> > > fi
>>>
>>> TSan does appear to have an interceptor for pthread_cond_clockwait, even
>>> if
>>> it lacks the others. Does this mean that this part is unnecessary?
>>>
>>
>> Ah good point, thanks. I grepped for clocklock but not clockwait.
>>
>
> In fact it seems like we don't need to change
> _GLIBCXX_USE_PTHREAD_RWLOCK_CLOCKLOCK either, because I don't get any tsan
> warnings for that. It doesn't have interceptors for
> pthread_rwlock_{rd,wr}lock, but it doesn't complain anyway (maybe it's
> simply not instrumenting the rwlock functions at all?!)
>
> So I'm now retesting with this version of the patch, which only touches
> the USE_PTHREAD_LOCKLOCK macro.
>
> Please take another look, thanks.
>
> LGTM.
next prev parent reply other threads:[~2023-05-15 19:59 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-10 11:20 [RFC] " Jonathan Wakely
2023-05-10 11:31 ` Jonathan Wakely
2023-05-11 12:19 ` Mike Crowe
2023-05-11 12:42 ` Jonathan Wakely
2023-05-11 20:52 ` [PATCH v2] " Jonathan Wakely
2023-05-12 10:30 ` Mike Crowe
2023-05-12 10:32 ` Jonathan Wakely
2023-05-15 12:03 ` Mike Crowe
2023-05-15 19:58 ` Thomas Rodgers [this message]
2023-05-11 15:54 ` [RFC] " Thomas Rodgers
2023-05-11 16:04 ` Jonathan Wakely
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