From: "René Scharfe" <rene.scharfe@lsrfire.ath.cx>
To: Junio C Hamano <gitster@pobox.com>
Cc: mhagger@alum.mit.edu, Jeff King <peff@peff.net>, git@vger.kernel.org
Subject: Re: [PATCH 3/3] refs: use strings directly in find_containing_dir()
Date: Wed, 23 May 2012 19:15:34 +0200 [thread overview]
Message-ID: <4FBD1B36.5060404@lsrfire.ath.cx> (raw)
In-Reply-To: <7v4nr625vf.fsf@alter.siamese.dyndns.org>
Am 23.05.2012 18:56, schrieb Junio C Hamano:
> René Scharfe<rene.scharfe@lsrfire.ath.cx> writes:
>
>> Am 23.05.2012 00:18, schrieb Junio C Hamano:
>>> René Scharfe<rene.scharfe@lsrfire.ath.cx> writes:
>>>
>>>> What has git grep to do with refs? It checks if the path in the command
>>>> above is a ref, which makes it iterate over all of them..
>>>
>>> Do you mean:
>>>
>>> /* Is it a rev? */
>>> get_sha1()
>>> -> ...
>>> -> get_sha1_basic()
>>> -> dwim_ref()
>>>
>>> callpath?
>>
>> Yes, indeed. Hmm, this is done even if the paths come after a
>> double-dash. Anyway, I don't consider the check to be a performance
>> issue, just a quick way to test the allocation count that i stumbled
>> upon while working on the recent grep patches.
>
> I was merely reacting "iterate over all of them"; dwim_ref() only checks
> if .git/blah, .git/refs/heads/blah, .git/refs/tags/blah, etc. exists and
> the number of checks do not depend on the number of refs you have, so I
> was wondering if I overlooked something that does for_each_ref() of
> everything.
Yeah, for loose refs that's true. However, I have 470 packed refs, and
this command:
$ valgrind --tool=exp-dhat ./git grep guess xdiff/xutils.c
reports (among other findings):
==28255== max-live: 30,334 in 470 blocks
==28255== tot-alloc: 30,334 in 470 blocks (avg size 64.54)
==28255== deaths: none (none of these blocks were freed)
==28255== acc-ratios: 7.76 rd, 0.95 wr (235,582 b-read, 28,924 b-written)
==28255== at 0x402AEE8: malloc (in /usr/lib/valgrind/vgpreload_exp-dhat-x86-linux.so)
==28255== by 0x813691D: xmalloc (wrapper.c:50)
==28255== by 0x8106B1A: create_ref_entry.constprop.8 (refs.c:250)
==28255== by 0x8107761: read_packed_refs (refs.c:817)
==28255== by 0x810785F: get_packed_refs (refs.c:843)
==28255== by 0x8107BE7: resolve_ref_unsafe (refs.c:1028)
==28255== by 0x81090AA: dwim_ref (refs.c:1549)
==28255== by 0x8122E06: get_sha1_1 (sha1_name.c:304)
==28255== by 0x81237EF: get_sha1_with_context_1 (sha1_name.c:1044)
==28255== by 0x8124016: get_sha1 (cache.h:795)
==28255== by 0x75782F65: ???
René
next prev parent reply other threads:[~2012-05-23 17:15 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-22 13:16 [PATCH] find_containing_dir(): allocate strbuf less extravagantly mhagger
2012-05-22 17:34 ` Jeff King
2012-05-22 18:50 ` [PATCH 1/3] refs: convert parameter of search_ref_dir() to length-limited string René Scharfe
2012-05-22 18:50 ` [PATCH 2/3] refs: convert parameter of create_dir_entry() " René Scharfe
2012-05-22 18:50 ` [PATCH 3/3] refs: use strings directly in find_containing_dir() René Scharfe
2012-05-22 21:27 ` Junio C Hamano
2012-05-22 22:11 ` René Scharfe
2012-05-22 22:18 ` Junio C Hamano
2012-05-23 16:20 ` René Scharfe
2012-05-23 16:56 ` Junio C Hamano
2012-05-23 17:15 ` René Scharfe [this message]
2012-05-24 4:34 ` Michael Haggerty
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