From: Eric Dumazet <dada1@cosmosbay.com>
To: Davide Libenzi <davidel@xmailserver.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ulrich Drepper <drepper@redhat.com>
Subject: Re: [patch 1/2] ufd v1 - unsequential O(1) fdmap core
Date: Mon, 4 Jun 2007 16:28:55 +0200 [thread overview]
Message-ID: <20070604162855.f98d1698.dada1@cosmosbay.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0706040633360.30231@alien.or.mcafeemobile.com>
On Mon, 4 Jun 2007 06:35:16 -0700 (PDT)
Davide Libenzi <davidel@xmailserver.org> wrote:
> On Mon, 4 Jun 2007, Eric Dumazet wrote:
>
> > You add conditional branches on very hot spots.
>
> Keep BS for the ones you argue usually, and that are not able to reply.
> You *still* two bitmaps, because allocation spaces are far apart. So the
> "if" will still be there.
I actually read your patches and spent time to see the pros and cons.
If you dont need reviewers, please dont post your patches on lkml.
If I am not mistaken, you added a test in fget()/fget_light(), which is a known hot point for said huge processes.
fget() dont need to access the bitmap at all. Using fd_slots means less (50%) file pointers per cache line.
On my machines, there is a ratio of 100/1 in cpu time for fget(),fget_light() against get_unused_fd().
next prev parent reply other threads:[~2007-06-04 14:29 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-02 22:59 Davide Libenzi
2007-06-03 21:19 ` Eric Dumazet
2007-06-03 22:51 ` Davide Libenzi
2007-06-04 6:08 ` Andrew Morton
2007-06-04 8:05 ` Ingo Molnar
2007-06-04 8:09 ` Ingo Molnar
2007-06-04 8:34 ` Andrew Morton
2007-06-04 8:42 ` Ingo Molnar
2007-06-04 8:47 ` Andrew Morton
2007-06-04 13:05 ` Davide Libenzi
2007-06-04 13:30 ` Davide Libenzi
2007-06-04 16:56 ` Andrew Morton
2007-06-04 17:57 ` Davide Libenzi
2007-06-04 10:28 ` Eric Dumazet
2007-06-04 12:55 ` Davide Libenzi
2007-06-04 13:25 ` Eric Dumazet
2007-06-04 13:33 ` Davide Libenzi
2007-06-04 13:35 ` Davide Libenzi
2007-06-04 14:28 ` Eric Dumazet [this message]
2007-06-04 14:53 ` Davide Libenzi
2007-06-04 14:12 ` Ingo Molnar
2007-06-04 14:27 ` Eric Dumazet
2007-06-05 20:37 ` Ingo Molnar
2007-06-05 20:50 ` Thomas Gleixner
2007-06-05 20:57 ` Eric Dumazet
2007-06-05 22:29 ` Eric Dumazet
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