From: Peter Zijlstra <peterz@infradead.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>,
Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Darren Hart <darren@dvhart.com>, Ingo Molnar <mingo@kernel.org>,
Michael Kerrisk <mtk.manpages@googlemail.com>,
Davidlohr Bueso <dave@stgolabs.net>, Chris Mason <clm@fb.com>,
"Carlos O'Donell" <carlos@redhat.com>,
Torvald Riegel <triegel@redhat.com>,
Eric Dumazet <edumazet@google.com>
Subject: Re: [patch V2 2/7] futex: Hash private futexes per process
Date: Mon, 30 May 2016 16:02:00 +0200 [thread overview]
Message-ID: <20160530140200.GE3193@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <c36795eb-eeff-ea48-30cd-3333e121c7ee@linutronix.de>
On Mon, May 30, 2016 at 03:59:51PM +0200, Sebastian Andrzej Siewior wrote:
> On 05/30/2016 03:49 PM, Peter Zijlstra wrote:
> >> The same thing can happen within a Task if you take my story from above
> >> and replace task with thread. Completely understood.
> >
> > Right; so I don't see the point of PREALLOCATE_HASH to cater for RT
> > workloads if it still doesn't guarantee anything, esp. if the failure
> > case is silent and obscure.
>
> So what do you suggest? Adding trace points in order to learn about
> possible collisions or using tickets (on top of this) to guarantee
> being collision free?
I have no idea about the ticket stuff, i've not seen it. But yes, you
need to somehow guarantee no collisions.
next prev parent reply other threads:[~2016-05-30 14:02 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-05 20:44 [patch V2 0/7] futex: Add support for process private hashing Thomas Gleixner
2016-05-05 20:44 ` [patch V2 1/7] futex: Add some more function commentry Thomas Gleixner
2016-05-06 17:37 ` Darren Hart
2016-05-05 20:44 ` [patch V2 2/7] futex: Hash private futexes per process Thomas Gleixner
2016-05-06 18:09 ` Darren Hart
2016-05-06 21:56 ` Darren Hart
2016-05-07 8:45 ` Thomas Gleixner
2016-05-11 21:08 ` Darren Hart
2016-05-07 8:44 ` Thomas Gleixner
2016-05-11 21:07 ` Darren Hart
2016-05-27 16:36 ` Sebastian Andrzej Siewior
2016-05-19 12:21 ` Peter Zijlstra
2016-05-27 16:52 ` Sebastian Andrzej Siewior
2016-05-30 8:43 ` Peter Zijlstra
2016-05-19 12:24 ` Peter Zijlstra
2016-05-27 17:10 ` Sebastian Andrzej Siewior
2016-05-30 8:58 ` Peter Zijlstra
2016-05-30 11:08 ` Sebastian Andrzej Siewior
2016-05-30 12:06 ` Peter Zijlstra
2016-05-30 13:37 ` Sebastian Andrzej Siewior
2016-05-30 13:49 ` Peter Zijlstra
2016-05-30 13:59 ` Sebastian Andrzej Siewior
2016-05-30 14:02 ` Peter Zijlstra [this message]
2016-05-05 20:44 ` [patch V2 4/7] futex: Add sysctl knobs for process private hash Thomas Gleixner
2016-05-06 18:22 ` Darren Hart
2016-05-27 17:33 ` Sebastian Andrzej Siewior
2016-05-05 20:44 ` [patch V2 3/7] futex: Add op for hash preallocation Thomas Gleixner
2016-05-06 18:18 ` Darren Hart
2016-05-07 8:47 ` Thomas Gleixner
2016-05-07 11:40 ` Thomas Gleixner
2016-05-19 12:28 ` Peter Zijlstra
2016-05-19 19:36 ` Darren Hart
2016-05-19 12:24 ` Peter Zijlstra
2016-05-19 19:38 ` Darren Hart
2016-05-20 4:50 ` Peter Zijlstra
2016-05-19 12:25 ` Peter Zijlstra
2016-05-27 17:27 ` Sebastian Andrzej Siewior
2016-05-30 8:59 ` Peter Zijlstra
2016-05-05 20:44 ` [patch V2 5/7] perf/bench/futex-hash: Support NUMA Thomas Gleixner
2016-05-05 20:44 ` [patch V2 6/7] perf/bench/futex-hash: Support preallocate hash table Thomas Gleixner
2016-05-05 20:44 ` [patch V2 7/7] futex.2: Document hash preallocation opcode Thomas Gleixner
-- strict thread matches above, loose matches on Subject: below --
2016-05-05 19:03 [patch V2 0/7] Sebastian Andrzej Siewior <bigeasy@linutronix.de>, Linus Torvalds <torvalds@linux-foundation.org>, Darren Hart <darren@dvhart.com>, Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>, Michael Kerrisk <mtk.manpages@googlemail.com>, Davidlohr Bueso <dave@stgolabs.net>, Chris Mason <clm@fb.com>, Carlos O'Donell <carlos@redhat.com>, Torvald Riegel <triegel@redhat.com>, Eric Dumazet <edumazet@google.com> Thomas Gleixner
2016-05-05 19:03 ` [patch V2 2/7] futex: Hash private futexes per process Thomas Gleixner
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