From: Joe Perches <joe@perches.com>
To: Alan Stern <stern@rowland.harvard.edu>, Kay Sievers <kay@vrfy.org>
Cc: Kernel development list <linux-kernel@vger.kernel.org>,
Jason Baron <jbaron@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>, Greg KH <greg@kroah.com>
Subject: Re: Excessive latency for dev_dbg?
Date: Wed, 23 May 2012 13:45:03 -0700 [thread overview]
Message-ID: <1337805903.1747.0.camel@joe2Laptop> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1205231627140.1248-100000@iolanthe.rowland.org>
cc'ing Kay.
On Wed, 2012-05-23 at 16:37 -0400, Alan Stern wrote:
> I just tried doing some testing of 3.4. Sequences of literally
> adjacent dev_dbg() calls -- with local interrupts disabled -- show up
> in the log buffer spaced at time intervals between 1 and 4
> milliseconds!
>
> This is with CONFIG_DYNAMIC_DEBUG not enabled, and CONFIG_PRINTK_TIME,
> CONFIG_PREEMPT, CONFIG_HIGH_RES_TIMERS, and CONFIG_HPET_TIMER all set
> to y.
>
> What's going on here? Did printk suddenly slow down a lot? Or has the
> timer code gone crazy?
next prev parent reply other threads:[~2012-05-23 20:45 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-23 20:37 Alan Stern
2012-05-23 20:45 ` Joe Perches [this message]
2012-05-24 2:12 ` Greg KH
2012-05-24 2:13 ` Joe Perches
2012-05-24 17:57 ` Alan Stern
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=1337805903.1747.0.camel@joe2Laptop \
--to=joe@perches.com \
--cc=greg@kroah.com \
--cc=jbaron@redhat.com \
--cc=kay@vrfy.org \
--cc=linux-kernel@vger.kernel.org \
--cc=stern@rowland.harvard.edu \
--cc=tglx@linutronix.de \
/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
all inboxes | Powered by JetHome®