From: Ramsay Jones <ramsay@ramsay1•demon.co.uk>
To: Jeff King <peff@peff•net>
Cc: git@vger•kernel.org, "Vicent Martí" <vicent@github•com>
Subject: Re: [PATCH v3 0/21] pack bitmaps
Date: Thu, 14 Nov 2013 23:09:40 +0000 [thread overview]
Message-ID: <52855834.3080608@ramsay1.demon.co.uk> (raw)
In-Reply-To: <20131114213320.GA16466@sigill.intra.peff.net>
On 14/11/13 21:33, Jeff King wrote:
> On Thu, Nov 14, 2013 at 07:19:38PM +0000, Ramsay Jones wrote:
>
>> Unfortunately, I didn't find time this weekend to finish the msvc build
>> fixes. However, after a quick squint at these patches, I think you have
>> almost done it for me! :-D
>>
>> I must have misunderstood the previous discussion, because my patch was
>> written on the assumption that the ewah directory wouldn't be "git-ified"
>> (e.g. #include git-compat-util.h).
>
> I think it was up for debate at some point, but we did decide to go
> ahead and git-ify. Please feel free to submit further fixups if you need
> them.
Yep, will do; at present it looks like that one-liner.
>
>>> - the ewah code used gcc's __builtin_ctzll, but did not provide a
>>> suitable fallback. We now provide a fallback in C.
>>
>> ... here.
>>
>> I was messing around with several implementations (including the use of
>> msvc compiler intrinsics) with the intention of doing some timing tests
>> etc. [I suspected my C fallback function (a different implementation to
>> yours) would be slightly faster.]
>
> Yeah, I looked around for several implementations, and ultimately wrote
> one that was the most readable to me. The one I found shortest and most
> inscrutable was:
>
> return popcount((x & -x) - 1);
>
> the details of which I still haven't worked through in my head. ;)
Yeah, I stumbled over that one too!
> I do think on most platforms that intrinsics or inline assembler are the
> way to go. My main goal was to get something correct that would let it
> compile everywhere, and then people can use that as a base for
> optimizing. Patches welcome. :)
Indeed, I can happily leave that to another day (or to someone else
more motivated ;-)
ATB,
Ramsay Jones
next prev parent reply other threads:[~2013-11-14 23:09 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-14 12:41 [PATCH v3 0/21] pack bitmaps Jeff King
2013-11-14 12:42 ` [PATCH v3 01/21] sha1write: make buffer const-correct Jeff King
2013-11-14 12:42 ` [PATCH v3 02/21] revindex: Export new APIs Jeff King
2013-11-14 12:42 ` [PATCH v3 03/21] pack-objects: Refactor the packing list Jeff King
2013-11-14 12:43 ` [PATCH v3 04/21] pack-objects: factor out name_hash Jeff King
2013-11-14 12:43 ` [PATCH v3 05/21] revision: allow setting custom limiter function Jeff King
2013-11-14 12:43 ` [PATCH v3 06/21] sha1_file: export `git_open_noatime` Jeff King
2013-11-14 12:43 ` [PATCH v3 07/21] compat: add endianness helpers Jeff King
2013-11-14 12:43 ` [PATCH v3 08/21] ewah: compressed bitmap implementation Jeff King
2013-11-14 12:44 ` [PATCH v3 09/21] documentation: add documentation for the bitmap format Jeff King
2013-11-14 12:44 ` [PATCH v3 10/21] pack-bitmap: add support for bitmap indexes Jeff King
2013-11-24 21:36 ` Thomas Rast
2013-11-25 15:04 ` [PATCH] Document khash Thomas Rast
2013-11-28 10:35 ` Jeff King
2013-11-27 9:08 ` [PATCH v3 10/21] pack-bitmap: add support for bitmap indexes Karsten Blees
2013-11-28 10:38 ` Jeff King
2013-12-03 14:40 ` Karsten Blees
2013-12-03 18:21 ` Jeff King
2013-12-07 20:52 ` Karsten Blees
2013-11-29 21:21 ` Thomas Rast
2013-12-02 16:12 ` Jeff King
2013-12-02 20:36 ` Junio C Hamano
2013-12-02 20:47 ` Jeff King
2013-12-02 21:43 ` Junio C Hamano
2013-11-14 12:45 ` [PATCH v3 11/21] pack-objects: use bitmaps when packing objects Jeff King
2013-12-07 15:47 ` Thomas Rast
2013-12-21 13:15 ` Jeff King
2013-11-14 12:45 ` [PATCH v3 12/21] rev-list: add bitmap mode to speed up object lists Jeff King
2013-12-07 16:05 ` Thomas Rast
2013-11-14 12:45 ` [PATCH v3 13/21] pack-objects: implement bitmap writing Jeff King
2013-12-07 16:32 ` Thomas Rast
2013-12-21 13:17 ` Jeff King
2013-11-14 12:45 ` [PATCH v3 14/21] repack: stop using magic number for ARRAY_SIZE(exts) Jeff King
2013-12-07 16:34 ` Thomas Rast
2013-11-14 12:46 ` [PATCH v3 15/21] repack: turn exts array into array-of-struct Jeff King
2013-12-07 16:34 ` Thomas Rast
2013-11-14 12:46 ` [PATCH v3 16/21] repack: handle optional files created by pack-objects Jeff King
2013-12-07 16:35 ` Thomas Rast
2013-11-14 12:46 ` [PATCH v3 17/21] repack: consider bitmaps when performing repacks Jeff King
2013-12-07 16:37 ` Thomas Rast
2013-11-14 12:46 ` [PATCH v3 18/21] count-objects: recognize .bitmap in garbage-checking Jeff King
2013-12-07 16:38 ` Thomas Rast
2013-11-14 12:46 ` [PATCH v3 19/21] t: add basic bitmap functionality tests Jeff King
2013-12-07 16:43 ` Thomas Rast
2013-12-21 13:22 ` Jeff King
2013-11-14 12:48 ` [PATCH v3 20/21] t/perf: add tests for pack bitmaps Jeff King
2013-12-07 16:51 ` Thomas Rast
2013-12-21 13:40 ` Jeff King
2013-11-14 12:48 ` [PATCH v3 21/21] pack-bitmap: implement optional name_hash cache Jeff King
2013-12-07 16:59 ` Thomas Rast
2013-11-14 19:19 ` [PATCH v3 0/21] pack bitmaps Ramsay Jones
2013-11-14 21:33 ` Jeff King
2013-11-14 23:09 ` Ramsay Jones [this message]
2013-11-18 21:16 ` Ramsay Jones
2013-11-16 10:28 ` Thomas Rast
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