From: Rik van Riel <riel@conectiva.com.br>
To: Denis Vlasenko <vda@port.imtp.ilyichevsk.odessa.ua>
Cc: William Lee Irwin III <wli@holomorphy.com>,
<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>
Subject: Re: [RFC][PATCH] iowait statistics
Date: Wed, 15 May 2002 11:03:38 -0300 (BRT) [thread overview]
Message-ID: <Pine.LNX.4.44L.0205151102030.9490-100000@duckman.distro.conectiva> (raw)
In-Reply-To: <200205151214.g4FCEqY13273@Port.imtp.ilyichevsk.odessa.ua>
On Wed, 15 May 2002, Denis Vlasenko wrote:
> I was investigating why sometimes in top I see idle % like
> 9384729374923.43%. It was caused by idle count in /proc/stat
> going backward sometimes.
Thanks for tracking down this bug.
> It can be fixed for SMP:
> * add spinlock
> or
> * add per_cpu_idle, account it too at timer/APIC int
> and get rid of idle % calculations for /proc/stat
>
> As a user, I vote for glitchless statistics even if they
> consume extra i++ cycle every timer int on every CPU.
Same for me. The last option is probably easiest to implement
and cheapest at run time. The extra "cost" will approach zero
once somebody takes the time to put the per-cpu stats on per
cpu cache lines, which I'm sure somebody will do once we have
enough per-cpu stats ;)
cheers,
Rik
--
http://www.linuxsymposium.org/2002/
"You're one of those condescending OLS attendants"
"Here's a nickle kid. Go buy yourself a real t-shirt"
http://www.surriel.com/ http://distro.conectiva.com/
next prev parent reply other threads:[~2002-05-15 14:47 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-05-14 1:19 [RFC][PATCH] iowait statistics Rik van Riel
2002-05-14 2:18 ` Andrew Morton
2002-05-14 12:30 ` Rik van Riel
2002-05-15 17:02 ` Denis Vlasenko
2002-05-16 7:41 ` Andrew Morton
2002-05-16 14:04 ` Denis Vlasenko
2002-05-14 15:39 ` William Lee Irwin III
2002-05-14 16:36 ` Rik van Riel
2002-05-14 16:54 ` William Lee Irwin III
2002-05-15 17:17 ` Denis Vlasenko
2002-05-15 14:03 ` Rik van Riel [this message]
2002-05-15 20:17 ` Denis Vlasenko
2002-05-15 16:13 ` Rik van Riel
2002-05-15 16:21 ` William Lee Irwin III
2002-05-15 17:00 ` William Lee Irwin III
2002-05-15 18:16 ` Bill Davidsen
2002-05-15 18:30 ` William Lee Irwin III
2002-05-15 18:33 ` Rik van Riel
2002-05-15 18:46 ` William Lee Irwin III
2002-05-15 19:00 ` Rik van Riel
2002-05-16 11:42 ` Denis Vlasenko
2002-05-16 11:14 ` Denis Vlasenko
2002-05-15 15:15 ` Bill Davidsen
2002-05-16 10:58 ` Denis Vlasenko
2002-05-14 18:19 ` Martin J. Bligh
2002-05-15 1:31 ` Bill Davidsen
2002-05-15 1:41 ` William Lee Irwin III
2002-05-15 14:39 ` Bill Davidsen
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=Pine.LNX.4.44L.0205151102030.9490-100000@duckman.distro.conectiva \
--to=riel@conectiva.com.br \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=vda@port.imtp.ilyichevsk.odessa.ua \
--cc=wli@holomorphy.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).