From: Linus Torvalds <torvalds@linux-foundation.org>
To: Nick Piggin <npiggin@kernel.dk>
Cc: "Américo Wang" <xiyou.wangcong@gmail.com>,
"Nick Piggin" <npiggin@gmail.com>,
"J. R. Okajima" <hooanon05@yahoo.co.jp>,
linux-arch@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: Big git diff speedup by avoiding x86 "fast string" memcmp
Date: Tue, 14 Dec 2010 23:12:08 -0800 [thread overview]
Message-ID: <AANLkTinZuGdZ4BMipbeLQH4e6UQ6qVNDCYeOxMpg7+og@mail.gmail.com> (raw)
In-Reply-To: <20101215055450.GC3398@amd>
On Tue, Dec 14, 2010 at 9:54 PM, Nick Piggin <npiggin@kernel.dk> wrote:
>
> That's what I would like to know, but I suspect that for very short
> strings we are dealing with, the custom loop will be fine for
> everybody.
Yeah, I can pretty much guarantee it for the common case of short
strings. Most path components are short enough that a "clever"
memcmp() is simply likely going to be slower than doing things
byte-per-byte.
That's especially true if we then in the future end up making it do a
long-by-long compare instead of the byte-by-byte one.
Linus
next prev parent reply other threads:[~2010-12-15 7:12 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-09 7:09 Big git diff speedup by avoiding x86 "fast string" memcmp Nick Piggin
2010-12-09 13:37 ` Borislav Petkov
2010-12-09 13:37 ` Borislav Petkov
2010-12-10 2:38 ` Nick Piggin
2010-12-10 2:38 ` Nick Piggin
2010-12-10 4:27 ` Nick Piggin
2010-12-10 14:23 ` J. R. Okajima
2010-12-13 1:45 ` Nick Piggin
2010-12-13 7:29 ` J. R. Okajima
2010-12-13 8:25 ` Nick Piggin
2010-12-13 8:25 ` Nick Piggin
2010-12-14 19:01 ` J. R. Okajima
2010-12-15 4:06 ` Nick Piggin
2010-12-15 5:57 ` J. R. Okajima
2010-12-15 13:15 ` Boaz Harrosh
2010-12-15 18:00 ` David Miller
2010-12-16 9:53 ` Boaz Harrosh
2010-12-16 13:13 ` Nick Piggin
2010-12-16 14:03 ` Boaz Harrosh
2010-12-16 14:15 ` Nick Piggin
2010-12-16 16:51 ` Linus Torvalds
2010-12-16 17:57 ` David Miller
2010-12-16 17:57 ` David Miller
2010-12-15 4:38 ` Américo Wang
2010-12-15 4:38 ` Américo Wang
2010-12-15 5:54 ` Nick Piggin
2010-12-15 7:12 ` Linus Torvalds [this message]
2010-12-15 23:09 ` Tony Luck
2010-12-16 2:34 ` Nick Piggin
-- strict thread matches above, loose matches on Subject: below --
2010-12-18 22:54 George Spelvin
2010-12-18 22:54 ` George Spelvin
2010-12-19 14:28 ` Boaz Harrosh
2010-12-19 14:28 ` Boaz Harrosh
2010-12-19 15:46 ` Nick Piggin
2010-12-19 17:06 ` George Spelvin
2010-12-21 9:26 ` Nick Piggin
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