From: Anton Blanchard <anton@samba.org>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: Kyle Moffett <mrmacman_g4@mac.com>,
"Michael K. Edwards" <medwards.linux@gmail.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Davide Libenzi <davidel@xmailserver.org>,
Avi Kivity <avi@argo.co.il>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [patch] epoll use a single inode ...
Date: Thu, 8 Mar 2007 20:51:02 -0600 [thread overview]
Message-ID: <20070309025102.GC24695@kryten> (raw)
In-Reply-To: <45EFBA14.9090307@cosmosbay.com>
> OK, 200 cycles...
>
> But what is the cost of the conditional branch you added in prefetch(x) ?
Much less than the tablewalk. On ppc64 a tablewalk of an address that is
not populated in the hashtable will incur 2 cacheline lookups (primary
and secondary buckets). This plus the MMU state machine overhead adds up.
Cue Linus rant about PowerPC MMU :)
Anton
next prev parent reply other threads:[~2007-03-09 2:52 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <45ED1A3C.6030707@argo.co.il>
2007-03-07 0:37 ` [patch] epoll use a single inode Davide Libenzi
2007-03-07 0:51 ` Linus Torvalds
2007-03-07 1:01 ` Davide Libenzi
2007-03-07 1:27 ` Linus Torvalds
2007-03-07 1:47 ` Davide Libenzi
2007-03-07 6:52 ` Eric Dumazet
2007-03-07 7:15 ` Davide Libenzi
2007-03-07 7:16 ` Eric Dumazet
2007-03-07 8:56 ` Christoph Hellwig
2007-03-07 17:21 ` Linus Torvalds
2007-03-07 17:02 ` Linus Torvalds
2007-03-07 17:31 ` Eric Dumazet
2007-03-07 17:36 ` Eric Dumazet
2007-03-07 17:45 ` Linus Torvalds
2007-03-07 18:06 ` Eric Dumazet
2007-03-07 18:30 ` Linus Torvalds
2007-03-07 18:52 ` Eric Dumazet
2007-03-07 19:07 ` Linus Torvalds
2007-03-07 22:14 ` Anton Blanchard
2007-03-07 22:57 ` Linus Torvalds
2007-03-08 1:25 ` Michael K. Edwards
2007-03-08 2:48 ` Kyle Moffett
2007-03-08 7:24 ` Eric Dumazet
2007-03-08 16:57 ` Valdis.Kletnieks
2007-03-09 1:34 ` Kyle Moffett
2007-03-09 2:52 ` Anton Blanchard
2007-03-09 2:51 ` Anton Blanchard [this message]
2007-03-08 3:20 ` Linus Torvalds
2007-03-08 8:37 ` Michael K. Edwards
2007-03-09 2:46 ` Anton Blanchard
2007-03-08 8:56 ` Christoph Hellwig
2007-03-08 9:42 ` Eric Dumazet
2007-03-08 10:21 ` Christoph Hellwig
2007-03-08 11:11 ` Eric Dumazet
2007-03-08 11:18 ` Christoph Hellwig
2007-03-08 15:52 ` Linus Torvalds
2007-03-08 16:58 ` [PATCH] VFS : Delay the dentry name generation on sockets and pipes Eric Dumazet
2007-03-08 18:29 ` Eric Dumazet
2007-03-09 10:18 ` [PATCH, take2] " Eric Dumazet
2007-03-09 18:22 ` Linus Torvalds
2007-03-10 1:21 ` [PATCH, take3] " Eric Dumazet
2007-03-08 20:00 ` [patch] epoll use a single inode Bob Copeland
[not found] <45ED046A.5010508@argo.co.il>
2007-03-06 7:27 ` Davide Libenzi
2007-03-05 21:25 Davide Libenzi
2007-03-05 21:52 ` Eric Dumazet
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