From: Mel Gorman <mgorman@techsingularity.net>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Jan Kara <jack@suse.cz>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] fsnotify: Rearrange fast path to minimise overhead when there is no watcher
Date: Wed, 10 Jun 2020 13:59:20 +0100 [thread overview]
Message-ID: <20200610125920.GM3127@techsingularity.net> (raw)
In-Reply-To: <CAOQ4uxhbE46S65-icLhaJqT+jKqz-ZdX=Ypm9hAt9Paeb+huhQ@mail.gmail.com>
On Mon, Jun 08, 2020 at 11:39:26PM +0300, Amir Goldstein wrote:
> > Let me add your optimizations on top of my branch with the needed
> > adaptations and send you a branch for testing.
>
> https://github.com/amir73il/linux/commits/fsnotify_name-for-mel
>
Sorry for the delay getting back. The machine was busy with other tests
and it took a while to reach this on the queue. Fairly good news
hackbench-process-pipes
5.7.0 5.7.0 5.7.0 5.7.0
vanilla fastfsnotify-v1r1 amir-20200608 amir-for-mel
Amean 1 0.4837 ( 0.00%) 0.4630 * 4.27%* 0.4967 * -2.69%* 0.4680 ( 3.24%)
Amean 3 1.5447 ( 0.00%) 1.4557 ( 5.76%) 1.6587 * -7.38%* 1.4807 ( 4.14%)
Amean 5 2.6037 ( 0.00%) 2.4363 ( 6.43%) 2.6400 ( -1.40%) 2.4900 ( 4.37%)
Amean 7 3.5987 ( 0.00%) 3.4757 ( 3.42%) 3.9040 * -8.48%* 3.5130 ( 2.38%)
Amean 12 5.8267 ( 0.00%) 5.6983 ( 2.20%) 6.2593 ( -7.43%) 5.6967 ( 2.23%)
Amean 18 8.4400 ( 0.00%) 8.1327 ( 3.64%) 8.9940 ( -6.56%) 7.7240 * 8.48%*
Amean 24 11.0187 ( 0.00%) 10.0290 * 8.98%* 11.7247 * -6.41%* 9.5793 * 13.06%*
Amean 30 13.1013 ( 0.00%) 12.8510 ( 1.91%) 14.0290 * -7.08%* 12.1630 ( 7.16%)
Amean 32 13.9190 ( 0.00%) 13.2410 ( 4.87%) 14.7140 * -5.71%* 13.2457 * 4.84%*
First two sets of results are vanilla kernel and just my patch respectively
to have two baselines. amir-20200608 is the first git branch you pointed
me to and amir-for-mel is this latest branch. Comparing the optimisation
and your series, we get
hackbench-process-pipes
5.7.0 5.7.0
fastfsnotify-v1r1 amir-for-mel
Amean 1 0.4630 ( 0.00%) 0.4680 ( -1.08%)
Amean 3 1.4557 ( 0.00%) 1.4807 ( -1.72%)
Amean 5 2.4363 ( 0.00%) 2.4900 ( -2.20%)
Amean 7 3.4757 ( 0.00%) 3.5130 ( -1.07%)
Amean 12 5.6983 ( 0.00%) 5.6967 ( 0.03%)
Amean 18 8.1327 ( 0.00%) 7.7240 ( 5.03%)
Amean 24 10.0290 ( 0.00%) 9.5793 ( 4.48%)
Amean 30 12.8510 ( 0.00%) 12.1630 ( 5.35%)
Amean 32 13.2410 ( 0.00%) 13.2457 ( -0.04%)
As you can see, your patches with the optimisation layered on top is
comparable to just the optimisation on its own. It's not universally
better but it would not look like a regression when comparing releases.
The differences are mostly within the noise as there is some variability
involved for this workload so I would not worry too much about it (caveats
are other machines may be different as well as other workloads). A minor
issue is that this is probably a bisection hazard. If a series is merged
and LKP points the finger somewhere in the middle of your series then
I suggest you ask them to test the optimisation commit ID to see if the
regression goes away.
Thanks Amir.
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2020-06-10 12:59 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-08 14:05 [PATCH] fsnotify: Rearrange fast path to minimise overhead when there is no watcher Mel Gorman
2020-06-08 15:03 ` Amir Goldstein
2020-06-08 16:06 ` Mel Gorman
2020-06-08 16:26 ` Amir Goldstein
2020-06-08 18:01 ` Mel Gorman
2020-06-08 18:12 ` Amir Goldstein
2020-06-08 20:39 ` Amir Goldstein
2020-06-10 12:59 ` Mel Gorman [this message]
2020-06-10 13:24 ` Amir Goldstein
2020-06-12 9:38 ` Amir Goldstein
2020-06-12 12:42 ` Mel Gorman
2020-06-08 15:19 ` Jan Kara
2020-06-08 16:50 ` Mel Gorman
2020-06-08 17:45 ` Amir Goldstein
-- strict thread matches above, loose matches on Subject: below --
2020-06-08 17:52 kernel test robot
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