From: "Paul E. McKenney" <paulmck@kernel.org>
To: David Laight <David.Laight@ACULAB.COM>
Cc: 'Willy Tarreau' <w@1wt.eu>, 'Nick Clifton' <nickc@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
"stern@rowland.harvard.edu" <stern@rowland.harvard.edu>,
"linux-toolchains@vger.kernel.org"
<linux-toolchains@vger.kernel.org>, Will Deacon <will@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"parri.andrea@gmail.com" <parri.andrea@gmail.com>,
"boqun.feng@gmail.com" <boqun.feng@gmail.com>,
"npiggin@gmail.com" <npiggin@gmail.com>,
"dhowells@redhat.com" <dhowells@redhat.com>,
"j.alglave@ucl.ac.uk" <j.alglave@ucl.ac.uk>,
"luc.maranget@inria.fr" <luc.maranget@inria.fr>,
"akiyks@gmail.com" <akiyks@gmail.com>,
"dlustig@nvidia.com" <dlustig@nvidia.com>,
"joel@joelfernandes.org" <joel@joelfernandes.org>,
"torvalds@linux-foundation.org" <torvalds@linux-foundation.org>
Subject: Re: Control Dependencies vs C Compilers
Date: Tue, 6 Oct 2020 09:31:41 -0700 [thread overview]
Message-ID: <20201006163141.GK29330@paulmck-ThinkPad-P72> (raw)
In-Reply-To: <e31a06a9c1e04b6c8c054b1fed3f897b@AcuMS.aculab.com>
On Tue, Oct 06, 2020 at 04:22:10PM +0000, David Laight wrote:
> From: Willy Tarreau
> > Sent: 06 October 2020 17:11
> >
> > On Tue, Oct 06, 2020 at 08:50:52AM -0700, Paul E. McKenney wrote:
> > > Comparing 25+ assembly languages to but two compilers most definitely
> > > motivates looking hard at doing something with the compilers.
> >
> > +1, especially since the kernel is not special; anyone working with
> > threads faces the same issues in userland, which are often hidden
> > behind the implicit whole-memory clobbers of certain operations or
> > the call to mutex manipulation functions, but which become a reality
> > again as soon as you go slightly away from these and try to use
> > lockless mechanisms.
>
> AFAICT most windows and android apps completely ignore the problem
> of thread locking - which is why the crash and lock up all the time :-)
>
> I've spent most of the day looking at some library traces from a
> customer bug.
> I almost suspect a bug in the pthread mutex code on their system.
> They are using a nice, modern, 3.10.0-957.el7.x86_64 kernel.
It would be good if the compiler were more helpful! Failing that, if
-something- could be more helpful!!!
Thanx, Paul
next prev parent reply other threads:[~2020-10-06 16:31 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-06 11:47 Control Dependencies vs C Compilers Peter Zijlstra
2020-10-06 12:37 ` David Laight
2020-10-06 12:49 ` Willy Tarreau
2020-10-06 13:31 ` Peter Zijlstra
2020-10-06 14:23 ` stern
2020-10-06 14:43 ` Peter Zijlstra
2020-10-06 15:16 ` Nick Clifton
2020-10-06 15:37 ` David Laight
2020-10-06 15:50 ` Paul E. McKenney
2020-10-06 16:10 ` Willy Tarreau
2020-10-06 16:22 ` David Laight
2020-10-06 16:31 ` Paul E. McKenney [this message]
2020-10-06 15:07 ` David Laight
2020-10-06 21:20 ` Florian Weimer
2020-10-07 9:32 ` Peter Zijlstra
2020-10-07 10:20 ` Florian Weimer
2020-10-07 11:50 ` Peter Zijlstra
2020-10-07 17:11 ` Paul E. McKenney
2020-10-07 21:07 ` Peter Zijlstra
2020-10-07 21:20 ` Paul E. McKenney
2020-10-07 10:30 ` Willy Tarreau
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