linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Steven Rostedt <rostedt@goodmis.org>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Tejun Heo <tj@kernel.org>,
	akpm@linux-foundation.org, linux-mm@kvack.org,
	Cong Wang <xiyou.wangcong@gmail.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Mel Gorman <mgorman@suse.de>, Michal Hocko <mhocko@kernel.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	Peter Zijlstra <peterz@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Jan Kara <jack@suse.cz>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
	rostedt@home.goodmis.org, Byungchul Park <byungchul.park@lge.com>,
	Pavel Machek <pavel@ucw.cz>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 0/2] printk: Console owner and waiter logic cleanup
Date: Tue, 16 Jan 2018 11:06:33 -0500	[thread overview]
Message-ID: <20180116110633.56f48cf7@gandalf.local.home> (raw)
In-Reply-To: <20180116061013.GA19801@jagdpanzerIV>

On Tue, 16 Jan 2018 15:10:13 +0900
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> wrote:

> overall that's very close to what I have in one of my private branches.
> console_trylock_spinning() for some reason does not perform really
> well on my made-up internal printk torture tests. it seems that I

One thing I noticed in my test with the module that does printks on all
cpus, was that the patch spreads out the processing of the consoles.
Before my patch, one printk user would be doing all the work, and all
the other printks only had to load their data into the logbuf then
exit. The majority of printks took a few microseconds, which looks
great if you ignore the one worker that is taking milliseconds to
complete. After my patch, since a printk that comes in while another
one was running would block, then it would start printing, it did
lengthen the time for individual printks to finish. Worst case it
would double the time to do printk. But it removed the burden of a
single printk doing all the work for all new printks that came in.

In other words, I would expect this to make printk on average slower.
But no longer unlimited.

-- Steve


> have a much better stability (no lockups and so on) when I also let
> printk_kthread to sleep on console_sem(). but I will look further.

  parent reply	other threads:[~2018-01-16 16:06 UTC|newest]

Thread overview: 140+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-10 13:24 [PATCH v5 0/2] printk: Console owner and waiter logic cleanup Petr Mladek
2018-01-10 13:24 ` [PATCH v5 1/2] printk: Add console owner and waiter logic to load balance console writes Petr Mladek
2018-01-10 16:50   ` Steven Rostedt
2018-01-12 16:54   ` Steven Rostedt
2018-01-12 17:11     ` Steven Rostedt
2018-01-17 19:13       ` Rasmus Villemoes
2018-01-17 19:33         ` Steven Rostedt
2018-01-19  9:51         ` Sergey Senozhatsky
2018-01-18 22:03     ` Pavel Machek
2018-01-19  0:20       ` Steven Rostedt
2018-01-17  2:19   ` Byungchul Park
2018-01-17  4:54     ` Byungchul Park
2018-01-17  7:34     ` Byungchul Park
2018-01-17 12:04     ` Petr Mladek
2018-01-18  1:53       ` Byungchul Park
2018-01-18  1:57         ` Byungchul Park
2018-01-18  2:19         ` Steven Rostedt
2018-01-18  4:01           ` Byungchul Park
2018-01-18 15:21             ` Steven Rostedt
2018-01-19  2:37               ` Byungchul Park
2018-01-19  3:27                 ` Steven Rostedt
2018-01-22  2:31                   ` Byungchul Park
2018-01-10 13:24 ` [PATCH v5 2/2] printk: Hide console waiter logic into helpers Petr Mladek
2018-01-10 17:52   ` Steven Rostedt
2018-01-11 12:03     ` Petr Mladek
2018-01-12 15:37       ` Steven Rostedt
2018-01-12 16:08         ` Petr Mladek
2018-01-12 16:36           ` Steven Rostedt
2018-01-15 16:08             ` Petr Mladek
2018-01-16  5:05               ` Sergey Senozhatsky
2018-01-10 14:05 ` [PATCH v5 0/2] printk: Console owner and waiter logic cleanup Tejun Heo
2018-01-10 16:29   ` Petr Mladek
2018-01-10 17:02     ` Tejun Heo
2018-01-10 18:21       ` Peter Zijlstra
2018-01-10 18:30         ` Tejun Heo
2018-01-10 18:41           ` Peter Zijlstra
2018-01-10 19:05             ` Tejun Heo
2018-01-11  5:15         ` Sergey Senozhatsky
2018-01-10 18:22       ` Steven Rostedt
2018-01-10 18:36         ` Tejun Heo
2018-01-10 18:40       ` Mathieu Desnoyers
2018-01-11  7:36         ` Sergey Senozhatsky
2018-01-11 11:24           ` Petr Mladek
2018-01-11 13:19             ` Sergey Senozhatsky
2018-01-24  9:36       ` Peter Zijlstra
2018-01-24 18:46         ` Tejun Heo
2018-05-09  8:58       ` Sergey Senozhatsky
2018-01-10 18:54     ` Steven Rostedt
2018-01-11  5:10     ` Sergey Senozhatsky
2018-01-10 18:05   ` Steven Rostedt
2018-01-10 18:12     ` Tejun Heo
2018-01-10 18:14       ` Tejun Heo
2018-01-10 18:45         ` Steven Rostedt
2018-01-10 18:41       ` Steven Rostedt
2018-01-10 18:57         ` Tejun Heo
2018-01-10 19:17           ` Steven Rostedt
2018-01-10 19:34             ` Tejun Heo
2018-01-10 19:44               ` Steven Rostedt
2018-01-10 22:44                 ` Tejun Heo
2018-01-11  5:35             ` Sergey Senozhatsky
2018-01-11  4:58     ` Sergey Senozhatsky
2018-01-11  9:34       ` Petr Mladek
2018-01-11 10:38         ` Sergey Senozhatsky
2018-01-11 11:50           ` Petr Mladek
2018-01-11 16:29           ` Steven Rostedt
2018-01-12  1:30             ` Steven Rostedt
2018-01-12  2:55               ` Steven Rostedt
2018-01-12  4:20                 ` Steven Rostedt
2018-01-16 19:44                 ` Tejun Heo
2018-01-17  9:12                   ` Petr Mladek
2018-01-17 15:15                     ` Tejun Heo
2018-01-17 17:12                       ` Steven Rostedt
2018-01-17 18:42                         ` Steven Rostedt
2018-01-19 18:20                           ` Steven Rostedt
2018-01-20  7:14                             ` Sergey Senozhatsky
2018-01-20 15:49                               ` Steven Rostedt
2018-01-21 14:15                                 ` Sergey Senozhatsky
2018-01-21 21:04                                   ` Steven Rostedt
2018-01-22  8:56                                     ` Sergey Senozhatsky
2018-01-22 10:28                                       ` Sergey Senozhatsky
2018-01-22 10:36                                         ` Sergey Senozhatsky
2018-01-23  6:40                                   ` Sergey Senozhatsky
2018-01-23  7:05                                     ` Sergey Senozhatsky
2018-01-23  7:31                                     ` Sergey Senozhatsky
2018-01-23 14:56                                     ` Steven Rostedt
2018-01-23 15:21                                       ` Sergey Senozhatsky
2018-01-23 15:41                                         ` Steven Rostedt
2018-01-23 15:43                                           ` Tejun Heo
2018-01-23 16:12                                             ` Sergey Senozhatsky
2018-01-23 16:13                                             ` Steven Rostedt
2018-01-23 17:21                                               ` Tejun Heo
2018-04-23  5:35                                             ` Sergey Senozhatsky
2018-01-23 16:01                                           ` Sergey Senozhatsky
2018-01-23 16:24                                             ` Steven Rostedt
2018-01-24  2:11                                               ` Sergey Senozhatsky
2018-01-24  2:52                                                 ` Steven Rostedt
2018-01-24  4:44                                                   ` Sergey Senozhatsky
2018-01-23 17:22                                             ` Tejun Heo
2018-01-20 12:19                             ` Tejun Heo
2018-01-20 14:51                               ` Steven Rostedt
2018-01-17 20:05                         ` Tejun Heo
2018-01-18  5:43                           ` Sergey Senozhatsky
2018-01-18 11:51                           ` Petr Mladek
2018-01-18  5:42                         ` Sergey Senozhatsky
2018-01-12  3:12               ` Sergey Senozhatsky
2018-01-12  2:56             ` Sergey Senozhatsky
2018-01-12  3:21               ` Steven Rostedt
2018-01-12 10:05                 ` Sergey Senozhatsky
2018-01-12 12:21                   ` Steven Rostedt
2018-01-12 12:55                     ` Petr Mladek
2018-01-13  7:31                       ` Sergey Senozhatsky
2018-01-15  8:51                         ` Petr Mladek
2018-01-15  9:48                           ` Sergey Senozhatsky
2018-01-16  5:16                           ` Sergey Senozhatsky
2018-01-16  9:08                             ` Petr Mladek
2018-01-15 12:08                       ` Steven Rostedt
2018-01-16  4:51                         ` Sergey Senozhatsky
2018-01-13  7:28                     ` Sergey Senozhatsky
2018-01-15 10:17                       ` Petr Mladek
2018-01-15 11:50                         ` Petr Mladek
2018-01-16  6:10                           ` Sergey Senozhatsky
2018-01-16  9:36                             ` Petr Mladek
2018-01-16 10:10                               ` Sergey Senozhatsky
2018-01-16 16:06                             ` Steven Rostedt [this message]
2018-01-16  5:23                         ` Sergey Senozhatsky
2018-01-15 12:06                       ` Steven Rostedt
2018-01-15 14:45                         ` Petr Mladek
2018-01-16  2:23                           ` Sergey Senozhatsky
2018-01-16  4:47                             ` Sergey Senozhatsky
2018-01-16 10:19                               ` Petr Mladek
2018-01-17  2:24                                 ` Sergey Senozhatsky
2018-01-16 15:45                               ` Steven Rostedt
2018-01-17  2:18                                 ` Sergey Senozhatsky
2018-01-17 13:04                                   ` Petr Mladek
2018-01-17 15:24                                     ` Steven Rostedt
2018-01-18  4:31                                     ` Sergey Senozhatsky
2018-01-18 15:22                                       ` Steven Rostedt
2018-01-16 10:13                             ` Petr Mladek
2018-01-17  6:29                               ` Sergey Senozhatsky
2018-01-16  1:46                         ` Sergey Senozhatsky

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180116110633.56f48cf7@gandalf.local.home \
    --to=rostedt@goodmis.org \
    --cc=akpm@linux-foundation.org \
    --cc=byungchul.park@lge.com \
    --cc=dave.hansen@intel.com \
    --cc=hannes@cmpxchg.org \
    --cc=jack@suse.cz \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mathieu.desnoyers@efficios.com \
    --cc=mgorman@suse.de \
    --cc=mhocko@kernel.org \
    --cc=pavel@ucw.cz \
    --cc=penguin-kernel@I-love.SAKURA.ne.jp \
    --cc=peterz@infradead.org \
    --cc=pmladek@suse.com \
    --cc=rostedt@home.goodmis.org \
    --cc=sergey.senozhatsky.work@gmail.com \
    --cc=sergey.senozhatsky@gmail.com \
    --cc=tj@kernel.org \
    --cc=torvalds@linux-foundation.org \
    --cc=vbabka@suse.cz \
    --cc=xiyou.wangcong@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).