From: Peter Zijlstra <peterz@infradead.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ingo Molnar <mingo@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Tejun Heo <tj@kernel.org>, Suren Baghdasaryan <surenb@google.com>,
Vinayak Menon <vinmenon@codeaurora.org>,
Christopher Lameter <cl@linux.com>,
Mike Galbraith <efault@gmx.de>,
Shakeel Butt <shakeelb@google.com>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH 08/10] psi: pressure stall information for CPU, memory, and IO
Date: Sat, 14 Jul 2018 11:02:44 +0200 [thread overview]
Message-ID: <20180714090244.GC4920@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20180713161756.GA21168@cmpxchg.org>
On Fri, Jul 13, 2018 at 12:17:56PM -0400, Johannes Weiner wrote:
> On Fri, Jul 13, 2018 at 11:21:53AM +0200, Peter Zijlstra wrote:
> > On Thu, Jul 12, 2018 at 01:29:40PM -0400, Johannes Weiner wrote:
> > > +static inline void psi_ttwu_dequeue(struct task_struct *p)
> > > +{
> > > + if (psi_disabled)
> > > + return;
> > > + /*
> > > + * Is the task being migrated during a wakeup? Make sure to
> > > + * deregister its sleep-persistent psi states from the old
> > > + * queue, and let psi_enqueue() know it has to requeue.
> > > + */
> > > + if (unlikely(p->in_iowait || (p->flags & PF_MEMSTALL))) {
> > > + struct rq_flags rf;
> > > + struct rq *rq;
> > > + int clear = 0;
> > > +
> > > + if (p->in_iowait)
> > > + clear |= TSK_IOWAIT;
> > > + if (p->flags & PF_MEMSTALL)
> > > + clear |= TSK_MEMSTALL;
> > > +
> > > + rq = __task_rq_lock(p, &rf);
> > > + update_rq_clock(rq);
> > > + psi_task_change(p, rq_clock(rq), clear, 0);
> > > + p->sched_psi_wake_requeue = 1;
> > > + __task_rq_unlock(rq, &rf);
> > > + }
> > > +}
> >
> > Still NAK, what happened to this here:
> That's my thought process, anyway. I'd be more than happy to make this
> more lightweight, but I don't see a way to do it without losing
> significant functional precision.
I think you're going to have to. We put a lot of effort into not taking
the old rq->lock on remote wakeups and got a significant performance
benefit from that.
You just utterly destroyed that for workloads with a high number of
iowait wakeups.
next prev parent reply other threads:[~2018-07-14 9:02 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-12 17:29 [PATCH 0/10] psi: pressure stall information for CPU, memory, and IO v2 Johannes Weiner
2018-07-12 17:29 ` [PATCH 01/10] mm: workingset: don't drop refault information prematurely Johannes Weiner
2018-07-12 17:29 ` [PATCH 02/10] mm: workingset: tell cache transitions from workingset thrashing Johannes Weiner
2018-07-23 13:36 ` Arnd Bergmann
2018-07-23 15:23 ` Johannes Weiner
2018-07-23 15:35 ` Arnd Bergmann
2018-07-23 16:27 ` Johannes Weiner
2018-07-24 15:04 ` Will Deacon
2018-07-25 16:06 ` Will Deacon
2018-07-12 17:29 ` [PATCH 03/10] delayacct: track delays from thrashing cache pages Johannes Weiner
2018-07-12 17:29 ` [PATCH 04/10] sched: loadavg: consolidate LOAD_INT, LOAD_FRAC, CALC_LOAD Johannes Weiner
2018-07-12 17:29 ` [PATCH 05/10] sched: loadavg: make calc_load_n() public Johannes Weiner
2018-07-12 17:29 ` [PATCH 06/10] sched: sched.h: make rq locking and clock functions available in stats.h Johannes Weiner
2018-07-12 17:29 ` [PATCH 07/10] sched: introduce this_rq_lock_irq() Johannes Weiner
2018-07-12 17:29 ` [PATCH 08/10] psi: pressure stall information for CPU, memory, and IO Johannes Weiner
2018-07-13 9:21 ` Peter Zijlstra
2018-07-13 16:17 ` Johannes Weiner
2018-07-14 8:48 ` Peter Zijlstra
2018-07-14 9:02 ` Peter Zijlstra [this message]
2018-07-17 10:03 ` Peter Zijlstra
2018-07-18 21:56 ` Johannes Weiner
2018-07-17 14:16 ` Peter Zijlstra
2018-07-18 22:00 ` Johannes Weiner
2018-07-17 14:21 ` Peter Zijlstra
2018-07-18 22:03 ` Johannes Weiner
2018-07-17 15:01 ` Peter Zijlstra
2018-07-18 22:06 ` Johannes Weiner
2018-07-20 14:13 ` Johannes Weiner
2018-07-17 15:17 ` Peter Zijlstra
2018-07-18 22:11 ` Johannes Weiner
2018-07-17 15:32 ` Peter Zijlstra
2018-07-18 12:03 ` Peter Zijlstra
2018-07-18 12:22 ` Peter Zijlstra
2018-07-18 22:36 ` Johannes Weiner
2018-07-19 13:58 ` Peter Zijlstra
2018-07-19 9:26 ` Peter Zijlstra
2018-07-19 12:50 ` Johannes Weiner
2018-07-19 13:18 ` Peter Zijlstra
2018-07-19 15:08 ` Linus Torvalds
2018-07-19 17:54 ` Johannes Weiner
2018-07-19 18:47 ` Johannes Weiner
2018-07-19 20:31 ` Peter Zijlstra
2018-07-24 16:01 ` Johannes Weiner
2018-07-18 12:46 ` Peter Zijlstra
2018-07-18 13:56 ` Johannes Weiner
2018-07-18 16:31 ` Peter Zijlstra
2018-07-18 16:46 ` Johannes Weiner
2018-07-20 20:35 ` Peter Zijlstra
2018-07-12 17:29 ` [PATCH 09/10] psi: cgroup support Johannes Weiner
2018-07-12 20:08 ` Tejun Heo
2018-07-17 15:40 ` Peter Zijlstra
2018-07-24 15:54 ` Johannes Weiner
2018-07-12 17:29 ` [RFC PATCH 10/10] psi: aggregate ongoing stall events when somebody reads pressure Johannes Weiner
2018-07-12 23:45 ` Andrew Morton
2018-07-13 22:17 ` Johannes Weiner
2018-07-13 22:13 ` Suren Baghdasaryan
2018-07-13 22:49 ` Johannes Weiner
2018-07-13 23:34 ` Suren Baghdasaryan
2018-07-17 15:13 ` Peter Zijlstra
2018-07-12 17:37 ` [PATCH 0/10] psi: pressure stall information for CPU, memory, and IO v2 Linus Torvalds
2018-07-12 23:44 ` Andrew Morton
2018-07-13 22:14 ` Johannes Weiner
2018-07-16 15:57 ` Daniel Drake
2018-07-17 11:25 ` Michal Hocko
2018-07-17 12:13 ` Daniel Drake
2018-07-17 12:23 ` Michal Hocko
2018-07-25 22:57 ` Daniel Drake
2018-07-18 22:21 ` Johannes Weiner
2018-07-19 11:29 ` peter enderborg
2018-07-19 12:18 ` Johannes Weiner
2018-07-23 21:14 ` Balbir Singh
2018-07-24 15:15 ` Johannes Weiner
2018-07-26 1:07 ` Singh, Balbir
2018-07-26 20:07 ` Johannes Weiner
2018-07-27 23:40 ` Suren Baghdasaryan
2018-07-27 22:01 ` Pavel Machek
2018-07-30 15:40 ` Johannes Weiner
2018-07-30 17:39 ` Pavel Machek
2018-07-30 17:51 ` Tejun Heo
2018-07-30 17:54 ` Randy Dunlap
2018-07-30 18:05 ` Tejun Heo
2018-07-30 17:59 ` Pavel Machek
2018-07-30 18:07 ` Tejun Heo
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