From: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
To: Andrea Arcangeli <andrea@suse.de>
Cc: Richard Henderson <rth@twiddle.net>, linux-kernel@vger.kernel.org
Subject: Re: [patch] 2.4.4 alpha semaphores optimization
Date: Fri, 4 May 2001 13:15:28 +0400 [thread overview]
Message-ID: <20010504131528.A2228@jurassic.park.msu.ru> (raw)
In-Reply-To: <20010503194747.A552@jurassic.park.msu.ru> <20010503192848.V1162@athlon.random>
In-Reply-To: <20010503192848.V1162@athlon.random>; from andrea@suse.de on Thu, May 03, 2001 at 07:28:48PM +0200
On Thu, May 03, 2001 at 07:28:48PM +0200, Andrea Arcangeli wrote:
> I'd love if you could port it on top of this one and to fix it so that
> it can handle up to 2^32 sleepers and not only 2^16 like we have to do
> on the 32bit archs to get good performance:
>
> ftp://ftp.us.kernel.org/pub/linux/kernel/people/andrea/kernels/v2.4/2.4.4aa3/00_rwsem-11
It could be done without much pain for both "official" and your rwsem
implementations.
However, there are 3 reasons why I prefer 16-bit counters:
a. "max user processes" ulimit is much lower than 64K anyway;
b. "long" count would cost extra 8 bytes in the struct rw_semaphore;
c. I can use existing atomic routines which deal with ints.
Actually I'm more anxious about a __builtin_expect() problem,
and I'd like to hear Richard's comment on this...
Ivan.
next prev parent reply other threads:[~2001-05-04 9:16 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-05-03 15:47 Ivan Kokshaysky
2001-05-03 17:28 ` Andrea Arcangeli
2001-05-04 9:15 ` Ivan Kokshaysky [this message]
2001-05-04 14:33 ` Andrea Arcangeli
2001-05-04 17:02 ` Ivan Kokshaysky
2001-05-04 17:16 ` Andrea Arcangeli
2001-05-04 9:22 ` David Howells
2001-05-04 9:54 ` Ivan Kokshaysky
2001-05-04 16:46 ` Ivan Kokshaysky
2001-05-04 21:12 ` Richard Henderson
2001-05-05 13:55 ` Ivan Kokshaysky
2001-05-06 6:55 ` Ivan Kokshaysky
2001-05-04 21:13 ` Richard Henderson
2001-05-05 14:17 ` Ivan Kokshaysky
2001-05-05 17:06 ` __builtin_expect vs inlining Richard Henderson
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