From: Jeff King <peff@peff.net>
To: "Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>
Cc: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH] Preallocate hash tables when the number of inserts are known in advance
Date: Sun, 17 Mar 2013 04:51:07 -0400 [thread overview]
Message-ID: <20130317085107.GB934@sigill.intra.peff.net> (raw)
In-Reply-To: <1363490886-29729-1-git-send-email-pclouds@gmail.com>
On Sun, Mar 17, 2013 at 10:28:06AM +0700, Nguyen Thai Ngoc Duy wrote:
> This avoids unnecessary re-allocations and reinsertions. On webkit.git
> (i.e. about 182k inserts to the name hash table), this reduces about
> 100ms out of 3s user time.
Good idea.
I had a similar thought when analyzing the hashing behavior of
pack-objects' "Counting objects..." phase, but it had even less impact
there. The insertions are just drowned out by the number of lookups in
that case.
-Peff
prev parent reply other threads:[~2013-03-17 8:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-17 3:28 [PATCH] Preallocate hash tables when the number of inserts are known in advance Nguyễn Thái Ngọc Duy
2013-03-17 5:34 ` Junio C Hamano
2013-03-17 5:39 ` Duy Nguyen
2013-03-17 6:18 ` Junio C Hamano
2013-03-17 8:51 ` Jeff King [this message]
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