From: Keith Owens <kaos@ocs.com.au>
To: William Lee Irwin III <wli@holomorphy.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: cpu-2.5.64-1
Date: Sun, 16 Mar 2003 22:12:24 +1100 [thread overview]
Message-ID: <17275.1047813144@ocs3.intra.ocs.com.au> (raw)
In-Reply-To: Your message of "Sun, 16 Mar 2003 02:10:55 -0800." <20030316101055.GG20188@holomorphy.com>
On Sun, 16 Mar 2003 02:10:55 -0800,
William Lee Irwin III <wli@holomorphy.com> wrote:
>On Sun, Mar 16, 2003 at 08:19:31PM +1100, Keith Owens wrote:
>> Good, it lets us optimize for 1/32/64/lots of cpus. NR_CPUS > 8 *
>> sizeof(unsigned long) is the interesting case, it needs arrays.
>
>Hmm. It shouldn't make a difference with respect to optimizing them.
>My API passes transparently by reference:
>#define cpu_isset(cpu, map) test_bit(cpu, (map).mask)
Some of the 64 bit archs implement test_bit() as taking int * instead
of long *. That generates unoptimized code for the case of NR_CPUS <
64.
#if NR_CPUS < 64
#define cpu_isset(cpu, map) (map.mask & (1UL << (cpu)))
...
generates better code on those architectures. Yet another special case :(
next prev parent reply other threads:[~2003-03-16 11:01 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-03-11 4:24 cpu-2.5.64-1 William Lee Irwin III
2003-03-11 7:17 ` cpu-2.5.64-1 Zwane Mwaikambo
2003-03-11 8:25 ` cpu-2.5.64-1 Zwane Mwaikambo
2003-03-16 7:39 ` cpu-2.5.64-1 Keith Owens
2003-03-16 8:36 ` cpu-2.5.64-1 William Lee Irwin III
2003-03-16 9:19 ` cpu-2.5.64-1 Keith Owens
2003-03-16 9:46 ` cpu-2.5.64-1 William Lee Irwin III
2003-03-16 10:10 ` cpu-2.5.64-1 William Lee Irwin III
2003-03-16 11:12 ` Keith Owens [this message]
2003-03-16 11:32 ` cpu-2.5.64-1 William Lee Irwin III
2003-03-16 11:53 ` cpu-2.5.64-1 Keith Owens
2003-03-16 12:00 ` cpu-2.5.64-1 William Lee Irwin III
2003-03-16 12:42 ` cpu-2.5.64-1 Horst von Brand
2003-03-16 19:14 ` cpu-2.5.64-1 William Lee Irwin III
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