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From: Linus Torvalds <torvalds@linux-foundation.org>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: Dave Chinner <david@fromorbit.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Bob Peterson <rpeterso@redhat.com>,
	Wu Fengguang <fengguang.wu@intel.com>, LKP <lkp@01.org>,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression
Date: Wed, 10 Aug 2016 17:23:59 -0700	[thread overview]
Message-ID: <CA+55aFyQ6cjKOQZKEuQV9ch+aerW1Q6uGdv+pCS81rX0yjyR6w@mail.gmail.com> (raw)
In-Reply-To: <87a8gk17x7.fsf@yhuang-mobile.sh.intel.com>

On Wed, Aug 10, 2016 at 5:11 PM, Huang, Ying <ying.huang@intel.com> wrote:
>
> Here is the comparison result with perf-profile data.

Heh. The diff is actually harder to read than just showing A/B
state.The fact that the call chain shows up as part of the symbol
makes it even more so.

For example:

>       0.00 ± -1%      +Inf%       1.68 ±  1%  perf-profile.cycles-pp.__add_to_page_cache_locked.add_to_page_cache_lru.pagecache_get_page.grab_cache_page_write_begin.iomap_write_begin
>       1.80 ±  1%    -100.0%       0.00 ± -1%  perf-profile.cycles-pp.__add_to_page_cache_locked.add_to_page_cache_lru.pagecache_get_page.grab_cache_page_write_begin.xfs_vm_write_begin

Ok, so it went from 1.8% to 1.68%, and isn't actually that big of a
change, but it shows up as a big change because the caller changed
from xfs_vm_write_begin to iomap_write_begin.

There's a few other cases of that too.

So I think it would actually be easier to just see "what 20 functions
were the hottest" (or maybe 50) before and after separately (just
sorted by cycles), without the diff part. Because the diff is really
hard to read.

                 Linus

  reply	other threads:[~2016-08-11  0:24 UTC|newest]

Thread overview: 109+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-09 14:33 [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression kernel test robot
2016-08-10 18:24 ` Linus Torvalds
2016-08-10 23:08   ` Dave Chinner
2016-08-10 23:51     ` Linus Torvalds
2016-08-10 23:58       ` [LKP] " Huang, Ying
2016-08-11  0:11         ` Huang, Ying
2016-08-11  0:23           ` Linus Torvalds [this message]
2016-08-11  0:33             ` Huang, Ying
2016-08-11  1:00               ` Linus Torvalds
2016-08-11  4:46                 ` Dave Chinner
2016-08-15 17:22                   ` Huang, Ying
2016-08-16  0:08                     ` Dave Chinner
2016-08-11 15:57                 ` Christoph Hellwig
2016-08-11 16:55                   ` Linus Torvalds
2016-08-11 17:51                     ` Huang, Ying
2016-08-11 19:51                       ` Linus Torvalds
2016-08-11 20:00                         ` Christoph Hellwig
2016-08-11 20:35                           ` Linus Torvalds
2016-08-11 22:16                             ` Al Viro
2016-08-11 22:30                               ` Linus Torvalds
2016-08-11 21:16                           ` Huang, Ying
2016-08-11 21:40                             ` Linus Torvalds
2016-08-11 22:08                               ` Christoph Hellwig
2016-08-12  0:54                     ` Dave Chinner
2016-08-12  2:23                       ` Dave Chinner
2016-08-12  2:32                         ` Linus Torvalds
2016-08-12  2:52                         ` Christoph Hellwig
2016-08-12  3:20                           ` Linus Torvalds
2016-08-12  4:16                             ` Dave Chinner
2016-08-12  5:02                               ` Linus Torvalds
2016-08-12  6:04                                 ` Dave Chinner
2016-08-12  6:29                                   ` Ye Xiaolong
2016-08-12  8:51                                     ` Ye Xiaolong
2016-08-12 10:02                                       ` Dave Chinner
2016-08-12 10:43                                         ` Fengguang Wu
2016-08-13  0:30                                         ` [LKP] [lkp] " Christoph Hellwig
2016-08-13 21:48                                           ` Christoph Hellwig
2016-08-13 22:07                                             ` Fengguang Wu
2016-08-13 22:15                                               ` Christoph Hellwig
2016-08-13 22:51                                                 ` Fengguang Wu
2016-08-14 14:50                                                   ` Fengguang Wu
2016-08-14 16:17                                                     ` Christoph Hellwig
2016-08-14 23:46                                                       ` Dave Chinner
2016-08-14 23:57                                                       ` Fengguang Wu
2016-08-15 14:14                                                       ` Fengguang Wu
2016-08-15 21:22                                                         ` Dave Chinner
2016-08-16 12:20                                                           ` Fengguang Wu
2016-08-15 20:30                                                       ` Huang, Ying
2016-08-22 22:09                                                         ` Huang, Ying
2016-09-26  6:25                                                           ` Huang, Ying
2016-09-26 14:55                                                             ` Christoph Hellwig
2016-09-27  0:52                                                               ` Huang, Ying
2016-08-16 13:25                                                       ` Fengguang Wu
2016-08-13 23:32                                           ` Dave Chinner
2016-08-12  2:27                       ` Linus Torvalds
2016-08-12  3:56                         ` Dave Chinner
2016-08-12 18:03                           ` Linus Torvalds
2016-08-13 23:58                             ` Fengguang Wu
2016-08-15  0:48                             ` Dave Chinner
2016-08-15  1:37                               ` Linus Torvalds
2016-08-15  2:28                                 ` Dave Chinner
2016-08-15  2:53                                   ` Linus Torvalds
2016-08-15  5:00                                     ` Dave Chinner
     [not found]                                       ` <CA+55aFwva2Xffai+Eqv1Jn_NGryk3YJ2i5JoHOQnbQv6qVPAsw@mail.gmail.com>
     [not found]                                         ` <CA+55aFy14nUnJQ_GdF=j8Fa9xiH70c6fY2G3q5HQ01+8z1z3qQ@mail.gmail.com>
     [not found]                                           ` <CA+55aFxp+rLehC8c157uRbH459wUC1rRPfCVgvmcq5BrG9gkyg@mail.gmail.com>
2016-08-15 22:22                                             ` Dave Chinner
2016-08-15 22:42                                               ` Dave Chinner
2016-08-15 23:20                                                 ` Linus Torvalds
2016-08-15 23:48                                                   ` Linus Torvalds
2016-08-16  0:44                                                     ` Dave Chinner
2016-08-16 15:05                                                     ` Mel Gorman
2016-08-16 17:47                                                       ` Linus Torvalds
2016-08-17 15:48                                                         ` Michal Hocko
2016-08-17 16:42                                                           ` Michal Hocko
2016-08-17 15:49                                                         ` Mel Gorman
2016-08-18  0:45                                                           ` Mel Gorman
2016-08-18  7:11                                                             ` Dave Chinner
2016-08-18 13:24                                                               ` Mel Gorman
2016-08-18 17:55                                                                 ` Linus Torvalds
2016-08-18 21:19                                                                   ` Dave Chinner
2016-08-18 22:25                                                                     ` Linus Torvalds
2016-08-19  9:00                                                                       ` Michal Hocko
2016-08-19 10:49                                                                       ` Mel Gorman
2016-08-19 23:48                                                                         ` Dave Chinner
2016-08-20  1:08                                                                           ` Linus Torvalds
2016-08-20 12:16                                                                           ` Mel Gorman
2016-08-19 15:08                                                               ` Mel Gorman
2016-09-01 23:32                                                                 ` Dave Chinner
2016-09-06 15:37                                                                   ` Mel Gorman
2016-09-06 15:52                                                                     ` Huang, Ying
2016-08-24 15:40                                                             ` Huang, Ying
2016-08-25  9:37                                                               ` Mel Gorman
2016-08-18  2:44                                                           ` Dave Chinner
2016-08-16  0:15                                                   ` Linus Torvalds
2016-08-16  0:38                                                     ` Dave Chinner
2016-08-16  0:50                                                       ` Linus Torvalds
2016-08-16  0:19                                                   ` Dave Chinner
2016-08-16  1:51                                                     ` Linus Torvalds
2016-08-16 22:02                                                       ` Dave Chinner
2016-08-16 23:23                                                         ` Linus Torvalds
2016-08-15 23:01                                               ` Linus Torvalds
2016-08-16  0:17                                                 ` Dave Chinner
2016-08-16  0:45                                                   ` Linus Torvalds
2016-08-15  5:03                                     ` Ingo Molnar
2016-08-17 16:24                                       ` Peter Zijlstra
2016-08-15 12:58                             ` Fengguang Wu
2016-08-11  1:16               ` Dave Chinner
2016-08-11  1:32                 ` Dave Chinner
2016-08-11  2:36                   ` Ye Xiaolong
2016-08-11  3:05                     ` Dave Chinner
2016-08-12  1:26                 ` Dave Chinner

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