From: Linus Torvalds <torvalds@linux-foundation.org>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Travis <travis@sgi.com>,
Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: [git pull] cpus4096 fixes
Date: Sun, 27 Jul 2008 15:17:14 -0700 (PDT) [thread overview]
Message-ID: <alpine.LFD.1.10.0807271511120.3486@nehalem.linux-foundation.org> (raw)
In-Reply-To: <20080727210547.GC28946@ZenIV.linux.org.uk>
On Sun, 27 Jul 2008, Al Viro wrote:
>
> ITYM "one 32.5kB array" -
> (u64[65][64]){[1][0] = 1, [2][0] = 2, [3][0] = 4, ..., [64][0] = 1ULL<<63}
> would work just fine. You were saying...?
Yeah, you can optimize it even more, I agree. But even the _trivial_ one
gets you to linear memory use (rather than something that is O(n^2) in
number of CPU's) and makes the thing a non-issue. But yes, there's another
almost-factor-of-two that you can get by being clever.
But in fact, I think your optimization would not just use less memory, but
yes, it's also easier to write the initializer for (with just a couple of
levels of macros to avoid having to do 64 entries by hand).
So yes, make it so. Please.
Linus
next prev parent reply other threads:[~2008-07-27 22:21 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-27 19:06 Ingo Molnar
2008-07-27 20:15 ` Linus Torvalds
2008-07-27 21:03 ` Ingo Molnar
2008-07-28 18:42 ` Mike Travis
2008-07-27 21:05 ` Al Viro
2008-07-27 22:17 ` Linus Torvalds [this message]
2008-07-28 0:42 ` Rusty Russell
2008-07-28 3:06 ` Andrew Morton
2008-07-28 6:34 ` Rusty Russell
2008-07-28 6:58 ` Nick Piggin
2008-07-28 7:56 ` Ingo Molnar
2008-07-28 18:12 ` Mike Travis
2008-07-28 8:33 ` Ingo Molnar
2008-07-28 18:07 ` Mike Travis
2008-07-28 17:50 ` Mike Travis
2008-07-28 18:32 ` Linus Torvalds
2008-07-28 18:37 ` Linus Torvalds
2008-07-28 18:51 ` Ingo Molnar
2008-07-28 19:22 ` Mike Travis
2008-07-28 19:31 ` Mike Travis
2008-07-28 19:04 ` Mike Travis
2008-07-28 20:57 ` [rfc git pull] cpus4096 fixes, take 2 Ingo Molnar
2008-07-28 21:35 ` Ingo Molnar
2008-07-28 21:41 ` [build error] drivers/char/pcmcia/ipwireless/hardware.c:571: error: invalid use of undefined type 'struct ipw_network' Ingo Molnar
2008-07-28 22:06 ` Ingo Molnar
2008-07-28 22:20 ` Andrew Morton
2008-07-28 22:29 ` Ingo Molnar
2008-07-30 14:59 ` David Sterba
2008-07-30 15:11 ` James Bottomley
2008-07-30 15:14 ` Jiri Kosina
2008-07-28 21:36 ` [rfc git pull] cpus4096 fixes, take 2 Mike Travis
2008-07-29 1:45 ` Rusty Russell
2008-07-29 12:11 ` Ingo Molnar
2008-07-30 0:15 ` Rusty Russell
2008-07-28 18:46 ` [git pull] cpus4096 fixes Mike Travis
2008-07-28 19:13 ` Ingo Molnar
2008-07-29 1:33 ` Rusty Russell
2008-07-28 0:53 ` Rusty Russell
2008-07-28 8:16 ` Ingo Molnar
2008-07-28 13:21 ` Rusty Russell
2008-07-28 18:23 ` Mike Travis
2008-07-31 10:30 ` Ingo Molnar
2008-07-28 8:43 ` Ingo Molnar
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