From: David Laight <David.Laight@ACULAB.COM>
To: 'Steven Rostedt' <rostedt@goodmis.org>,
Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Cc: Petr Mladek <pmladek@suse.com>,
John Ogness <john.ogness@linutronix.de>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH printk 3/5] printk: use buffer pool for sprint buffers
Date: Wed, 30 Sep 2020 14:32:12 +0000 [thread overview]
Message-ID: <3d6c42b0734a4713b45647415a51bcc1@AcuMS.aculab.com> (raw)
In-Reply-To: <20200930093552.3684aee1@gandalf.local.home>
From: Steven Rostedt
> Sent: 30 September 2020 14:36
>
> On Wed, 30 Sep 2020 10:06:24 +0200
> Rasmus Villemoes <rasmus.villemoes@prevas.dk> wrote:
>
> > True. But remember that printk is called from _everywhere_, with all
> > sorts of locks held and/or preemption disabled or whatnot, and every
> > cycle spent in printk makes those windows wider. Doubling the cost of
> > every single printk by unconditionally doing vsnprintf() twice is a bad
> > idea.
>
> But the console output is usually magnitudes more expensive than the
> vsnprintf(), would doing it twice really make a difference?
Are there any strange %pX modifiers that do anything really horrid?
David
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Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2020-09-30 14:32 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-22 15:38 [PATCH printk 0/5] printk: remove logbuf_lock John Ogness
2020-09-22 15:38 ` [PATCH printk 1/5] printk: get new seq before enabling interrupts John Ogness
2020-09-23 14:17 ` Petr Mladek
2020-09-23 14:36 ` John Ogness
2020-09-22 15:38 ` [PATCH printk 2/5] printk: kmsg_dump_rewind_nolock: start from first record John Ogness
2020-09-23 14:52 ` Petr Mladek
2020-09-23 15:39 ` John Ogness
2020-09-22 15:38 ` [PATCH printk 3/5] printk: use buffer pool for sprint buffers John Ogness
2020-09-23 15:11 ` Petr Mladek
2020-09-23 15:21 ` David Laight
2020-09-23 16:41 ` Petr Mladek
2020-09-24 5:40 ` Sergey Senozhatsky
2020-09-24 8:45 ` Petr Mladek
2020-09-24 8:53 ` Sergey Senozhatsky
2020-09-24 9:49 ` Rasmus Villemoes
2020-09-25 8:15 ` Petr Mladek
2020-09-24 9:54 ` Rasmus Villemoes
2020-09-24 12:32 ` Rasmus Villemoes
2020-09-25 8:28 ` Petr Mladek
2020-09-30 8:06 ` Rasmus Villemoes
2020-09-30 8:51 ` Petr Mladek
2020-09-30 8:57 ` John Ogness
2020-09-30 13:35 ` Steven Rostedt
2020-09-30 14:32 ` David Laight [this message]
2020-10-01 7:15 ` Rasmus Villemoes
2020-10-01 7:58 ` Petr Mladek
2020-09-24 1:21 ` Sergey Senozhatsky
2020-09-24 6:17 ` Sergey Senozhatsky
2020-09-24 8:54 ` Petr Mladek
2020-09-24 9:06 ` Sergey Senozhatsky
2020-09-25 8:13 ` Petr Mladek
2020-09-22 15:38 ` [PATCH printk 4/5] printk: remove logbuf_lock, add syslog_lock John Ogness
2020-09-23 16:30 ` Petr Mladek
2020-09-24 8:45 ` Sergey Senozhatsky
2020-09-24 9:21 ` John Ogness
2020-09-22 15:38 ` [PATCH printk 5/5] printk: remove nmi safe buffers John Ogness
2020-09-23 16:36 ` Petr Mladek
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