From: Martin Schwidefsky <schwidefsky@de.ibm.com>
To: Paul Mackerras <paulus@ozlabs.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
Tony Luck <tony.luck@intel.com>,
Wanpeng Li <wanpeng.li@hotmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, Fenghua Yu <fenghua.yu@intel.com>,
Rik van Riel <riel@redhat.com>,
Stanislaw Gruszka <sgruszka@redhat.com>
Subject: Re: [PATCH 00/10] vtime: Delay cputime accounting to tick
Date: Tue, 6 Dec 2016 08:04:32 +0100 [thread overview]
Message-ID: <20161206080432.6a937476@mschwideX1> (raw)
In-Reply-To: <20161206042055.GB9068@fergus.ozlabs.ibm.com>
On Tue, 6 Dec 2016 15:20:55 +1100
Paul Mackerras <paulus@ozlabs.org> wrote:
> On Tue, Dec 06, 2016 at 03:32:13AM +0100, Frederic Weisbecker wrote:
> > This follows up Martin Schwidefsky's patch which propose to delay
> > cputime accounting to the tick in order to minimize the calls to
> > account_system_time() and alikes as these functions can carry quite some
> > overhead:
> >
> > http://lkml.kernel.org/r/20161121111728.13a0a3db@mschwide
> >
> > The set includes Martin's patch, rebased on top of tip:sched/core and
> > latest s390 changes, and extends it to the other implementations of
> > CONFIG_VIRT_CPU_ACCOUNTING_NATIVE (powerpc and ia64) along with a few
> > core changes to adapt the whole.
> >
> > Only built-tested though as I don't have access to any of these archs.
>
> The patches look reasonable at a quick look. I assume that to test
> them, we would want to run a guest in an overcommitted system, so as
> to get some steal time. Do you have any more specific suggestions as
> to what to run as a test? Just run some benchmark and see if the
> user/system/irq times look reasonable? Or do you have something more
> quantitative?
My quick test this morning showed that for s390 it works quite well.
I yet have to do more detailed tests to see if the numbers really
add up.
--
blue skies,
Martin.
"Reality continues to ruin my life." - Calvin.
next prev parent reply other threads:[~2016-12-06 7:06 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-06 2:32 [PATCH 00/10] vtime: Delay cputime accounting to tick Frederic Weisbecker
2016-12-06 2:32 ` [FIX][PATCH 01/10] powerpc32: Fix stale scaled stime on context switch Frederic Weisbecker
2016-12-06 2:32 ` [FIX][PATCH 02/10] ia64: Fix wrong start cputime assignment on task switch Frederic Weisbecker
2016-12-06 2:32 ` [PATCH 03/10] cputime: Allow accounting system time using cpustat index Frederic Weisbecker
2016-12-06 2:32 ` [PATCH 04/10] cputime: Export account_guest_time Frederic Weisbecker
2016-12-06 2:32 ` [PATCH 05/10] powerpc: Prepare accounting structure for cputime flush on tick Frederic Weisbecker
2016-12-06 2:32 ` [PATCH 06/10] powerpc: Migrate stolen_time field to accounting structure Frederic Weisbecker
2016-12-06 2:32 ` [PATCH 07/10] powerpc/vtime: Accumulate cputime and account only on tick/task switch Frederic Weisbecker
2016-12-06 2:32 ` [PATCH 08/10] ia64: " Frederic Weisbecker
2016-12-06 2:32 ` [PATCH 09/10] s390/cputime: delayed accounting of system time Frederic Weisbecker
2016-12-10 1:48 ` Frederic Weisbecker
2016-12-12 10:27 ` Martin Schwidefsky
2016-12-12 15:02 ` Frederic Weisbecker
2016-12-13 11:13 ` Martin Schwidefsky
2016-12-13 13:21 ` Martin Schwidefsky
2016-12-14 1:44 ` Frederic Weisbecker
2016-12-20 14:13 ` Martin Schwidefsky
2016-12-20 14:30 ` Frederic Weisbecker
2016-12-13 14:38 ` Frederic Weisbecker
2016-12-06 2:32 ` [PATCH 10/10] vtime: Rename vtime_account_user() to vtime_flush() Frederic Weisbecker
2016-12-06 4:20 ` [PATCH 00/10] vtime: Delay cputime accounting to tick Paul Mackerras
2016-12-06 7:04 ` Martin Schwidefsky [this message]
2016-12-06 14:34 ` Frederic Weisbecker
2016-12-06 8:40 ` Christian Borntraeger
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