From: Mel Gorman <mgorman@techsingularity.net>
To: Dave Chinner <david@fromorbit.com>
Cc: Tony Jones <tonyj@suse.de>, Michal Hocko <mhocko@suse.cz>,
Janani Ravichandran <janani.rvchndrn@gmail.com>,
Rik van Riel <riel@surriel.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, hannes@cmpxchg.org,
vdavydov@virtuozzo.com, vbabka@suse.cz,
kirill.shutemov@linux.intel.com, bywxiaobai@163.com
Subject: Re: [PATCH 1/3] Add a new field to struct shrinker
Date: Fri, 29 Jul 2016 14:00:06 +0100 [thread overview]
Message-ID: <20160729130005.GE2799@techsingularity.net> (raw)
In-Reply-To: <20160729001340.GM12670@dastard>
On Fri, Jul 29, 2016 at 10:13:40AM +1000, Dave Chinner wrote:
> On Thu, Jul 28, 2016 at 11:25:13AM +0100, Mel Gorman wrote:
> > On Thu, Jul 28, 2016 at 03:49:47PM +1000, Dave Chinner wrote:
> > > Seems you're all missing the obvious.
> > >
> > > Add a tracepoint for a shrinker callback that includes a "name"
> > > field, have the shrinker callback fill it out appropriately. e.g
> > > in the superblock shrinker:
> > >
> > > trace_shrinker_callback(shrinker, shrink_control, sb->s_type->name);
> > >
> >
> > That misses capturing the latency of the call unless there is a begin/end
> > tracepoint.
>
> Sure, but I didn't see that in the email talking about how to add a
> name. Even if it is a requirement, it's not necessary as we've
> already got shrinker runtime measurements from the
> trace_mm_shrink_slab_start and trace_mm_shrink_slab_end trace
> points. With the above callback event, shrinker call runtime is
> simply the time between the calls to the same shrinker within
> mm_shrink_slab start/end trace points.
>
Fair point. It's not that hard to correlate them.
> <SNIP>
>
> > My understanding was the point of the tracepoints was to get detailed
> > information on points where the kernel is known to stall for long periods
> > of time.
>
> First I've heard that's what tracepoints are supposed to be used
> for.
I meant the specific case of trace_X_begin followed by trace_X_end, not
tracepoints in general.
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2016-07-29 13:00 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-09 8:33 [PATCH 0/3] Add names of shrinkers and have tracepoints display them Janani Ravichandran
2016-07-09 8:43 ` [PATCH 1/3] Add a new field to struct shrinker Janani Ravichandran
2016-07-11 6:37 ` Michal Hocko
2016-07-11 14:12 ` Rik van Riel
2016-07-11 14:33 ` Michal Hocko
2016-07-20 14:41 ` Janani Ravichandran
2016-07-20 14:54 ` Michal Hocko
2016-07-23 1:27 ` Tony Jones
2016-07-23 4:05 ` Tony Jones
2016-07-23 19:43 ` Rik van Riel
2016-07-23 23:21 ` Tony Jones
2016-07-26 16:40 ` Tony Jones
2016-07-28 5:49 ` Dave Chinner
2016-07-28 10:25 ` Mel Gorman
2016-07-29 0:13 ` Dave Chinner
2016-07-29 13:00 ` Mel Gorman [this message]
2016-08-12 3:09 ` Tony Jones
2016-07-09 8:52 ` [PATCH 2/3] Update name field for all shrinker instances Janani Ravichandran
2016-07-13 0:43 ` Tony Jones
2016-07-09 9:05 ` [PATCH 3/3] Add name fields in shrinker tracepoint definitions Janani Ravichandran
2016-07-09 9:45 ` kbuild test robot
2016-07-11 14:18 ` Vlastimil Babka
2016-07-13 0:35 ` Tony Jones
2016-07-13 6:16 ` Janani Ravichandran
2016-07-13 19:12 ` Tony Jones
2016-07-13 19:48 ` Rik van Riel
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