From: Elijah Newren <newren@gmail.com>
To: "Nguyễn Thái Ngọc" <pclouds@gmail.com>
Cc: Ben Peart <Ben.Peart@microsoft.com>,
Git Mailing List <git@vger.kernel.org>,
Junio C Hamano <gitster@pobox.com>,
Ben Peart <peartben@gmail.com>, Jeff King <peff@peff.net>
Subject: Re: [PATCH v2 4/4] unpack-trees: cheaper index update when walking by cache-tree
Date: Fri, 10 Aug 2018 12:40:19 -0700 [thread overview]
Message-ID: <CABPp-BHMC8k3t2_9KzdJvg80e-nqwsbLUceTLNjQ=ST=9XthEA@mail.gmail.com> (raw)
In-Reply-To: <CACsJy8AeptcqwRC+DOrdhvk69kEQT6+S6M=0OGWBFOE5gihGzA@mail.gmail.com>
On Fri, Aug 10, 2018 at 12:30 PM Duy Nguyen <pclouds@gmail.com> wrote:
> On Fri, Aug 10, 2018 at 8:39 PM Elijah Newren <newren@gmail.com> wrote:
...
> > Why do we still need to go through add_index_entry()? I thought that
> > the whole point was that you already checked that at the current path,
> > the trees being unpacked were all equal and matched both the index and
> > the cache_tree. If so, why is there any need for an update at all?
> > (Did I read your all_trees_same_as_cache_tree() function wrong, and
> > you don't actually know these all match in some important way?)
>
> Unless fn is oneway_diff, we have to create a new index (in o->result)
> based on o->src_index and some other trees. So we have to add entries
Oh, right, o->src_index may not equal o->dst_index (because of people
like me who call it that way from merge-recursive.c) and even if it
does, we still have the temporary o->result in the mean time. I
should have remembered that; just didn't.
> to o->result and add_index_entry() is the way to do that (granted if
> we feel confident we could add ADD_CACHE_JUST_APPEND which makes it
> super cheap). This is the outcome of n-way merge,
>
> all_trees_same_as_cache_tree() only gurantees the input condition (all
> trees the same, index also the same) but it can't affect what fn does.
> I don't think we can just simply skip and not update anything (like
> o->diff_index_cached case) because o->result would be empty in the
> end. And we need to create (temporary) o->result before we can swap it
> to o->dst_index as the result of a merge operation.
>
...
> I have a feeling that you're thinking we can swap o->src_index to
> o->dst_index at the end? That might explain your confusion about
> o->result (or I misread your replies horribly) and the original
> index...
Yeah, thanks for figuring out my confusion and jogging my memory.
next prev parent reply other threads:[~2018-08-10 19:40 UTC|newest]
Thread overview: 121+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-18 20:45 [PATCH v1 0/3] [RFC] Speeding up checkout (and merge, rebase, etc) Ben Peart
2018-07-18 20:45 ` [PATCH v1 1/3] add unbounded Multi-Producer-Multi-Consumer queue Ben Peart
2018-07-18 20:57 ` Stefan Beller
2018-07-19 19:11 ` Junio C Hamano
2018-07-18 20:45 ` [PATCH v1 2/3] add performance tracing around traverse_trees() in unpack_trees() Ben Peart
2018-07-18 20:45 ` [PATCH v1 3/3] Add initial parallel version of unpack_trees() Ben Peart
2018-07-18 22:56 ` Junio C Hamano
2018-07-18 21:02 ` [PATCH v1 0/3] [RFC] Speeding up checkout (and merge, rebase, etc) Stefan Beller
2018-07-18 21:34 ` Jeff King
2018-07-23 15:48 ` Ben Peart
2018-07-23 17:03 ` Duy Nguyen
2018-07-23 20:51 ` Ben Peart
2018-07-24 4:20 ` Jeff King
2018-07-24 15:33 ` Duy Nguyen
2018-07-25 20:56 ` Ben Peart
2018-07-26 5:30 ` Duy Nguyen
2018-07-26 16:30 ` Duy Nguyen
2018-07-26 19:40 ` Junio C Hamano
2018-07-27 15:42 ` Duy Nguyen
2018-07-27 16:22 ` Ben Peart
2018-07-27 18:00 ` Duy Nguyen
2018-07-27 17:14 ` Junio C Hamano
2018-07-27 17:52 ` Duy Nguyen
2018-07-29 6:24 ` Duy Nguyen
2018-07-29 10:33 ` [PATCH v2 0/4] Speed up unpack_trees() Nguyễn Thái Ngọc Duy
2018-07-29 10:33 ` [PATCH v2 1/4] unpack-trees.c: add performance tracing Nguyễn Thái Ngọc Duy
2018-07-30 20:16 ` Ben Peart
2018-07-29 10:33 ` [PATCH v2 2/4] unpack-trees: optimize walking same trees with cache-tree Nguyễn Thái Ngọc Duy
2018-07-30 20:52 ` Ben Peart
2018-07-29 10:33 ` [PATCH v2 3/4] unpack-trees: reduce malloc in cache-tree walk Nguyễn Thái Ngọc Duy
2018-07-30 20:58 ` Ben Peart
2018-07-29 10:33 ` [PATCH v2 4/4] unpack-trees: cheaper index update when walking by cache-tree Nguyễn Thái Ngọc Duy
2018-08-08 18:46 ` Elijah Newren
2018-08-10 16:39 ` Duy Nguyen
2018-08-10 18:39 ` Elijah Newren
2018-08-10 19:30 ` Duy Nguyen
2018-08-10 19:40 ` Elijah Newren [this message]
2018-08-10 19:48 ` Duy Nguyen
2018-07-30 18:10 ` [PATCH v2 0/4] Speed up unpack_trees() Ben Peart
2018-07-31 15:31 ` Duy Nguyen
2018-07-31 16:50 ` Ben Peart
2018-07-31 17:31 ` Ben Peart
2018-08-01 16:38 ` Duy Nguyen
2018-08-08 20:53 ` Ben Peart
2018-08-09 8:16 ` Ben Peart
2018-08-10 16:08 ` Duy Nguyen
2018-08-10 15:51 ` Duy Nguyen
2018-07-30 21:04 ` Ben Peart
2018-08-04 5:37 ` [PATCH v3 " Nguyễn Thái Ngọc Duy
2018-08-04 5:37 ` [PATCH v3 1/4] unpack-trees: add performance tracing Nguyễn Thái Ngọc Duy
2018-08-04 5:37 ` [PATCH v3 2/4] unpack-trees: optimize walking same trees with cache-tree Nguyễn Thái Ngọc Duy
2018-08-08 18:23 ` Elijah Newren
2018-08-10 16:29 ` Duy Nguyen
2018-08-10 18:48 ` Elijah Newren
2018-08-04 5:37 ` [PATCH v3 3/4] unpack-trees: reduce malloc in cache-tree walk Nguyễn Thái Ngọc Duy
2018-08-08 18:30 ` Elijah Newren
2018-08-04 5:37 ` [PATCH v3 4/4] unpack-trees: cheaper index update when walking by cache-tree Nguyễn Thái Ngọc Duy
2018-08-06 15:48 ` [PATCH v3 0/4] Speed up unpack_trees() Junio C Hamano
2018-08-06 15:59 ` Duy Nguyen
2018-08-06 18:59 ` Junio C Hamano
2018-08-08 17:00 ` Ben Peart
2018-08-08 17:46 ` Junio C Hamano
2018-08-08 18:12 ` Junio C Hamano
2018-08-08 18:39 ` Junio C Hamano
2018-08-10 16:53 ` Duy Nguyen
2018-08-12 8:15 ` [PATCH v4 0/5] " Nguyễn Thái Ngọc Duy
2018-08-12 8:15 ` [PATCH v4 1/5] trace.h: support nested performance tracing Nguyễn Thái Ngọc Duy
2018-08-13 18:39 ` Ben Peart
2018-08-12 8:15 ` [PATCH v4 2/5] unpack-trees: add " Nguyễn Thái Ngọc Duy
2018-08-12 10:05 ` Thomas Adam
2018-08-13 18:50 ` Junio C Hamano
2018-08-13 18:44 ` Ben Peart
2018-08-13 19:25 ` Jeff King
2018-08-13 19:36 ` Stefan Beller
2018-08-13 20:11 ` Ben Peart
2018-08-13 19:52 ` Duy Nguyen
2018-08-13 21:47 ` Jeff King
2018-08-13 22:41 ` Junio C Hamano
2018-08-14 18:19 ` Jeff Hostetler
2018-08-14 18:32 ` Duy Nguyen
2018-08-14 18:44 ` Stefan Beller
2018-08-14 18:51 ` Duy Nguyen
2018-08-14 19:54 ` Jeff King
2018-08-14 20:52 ` Junio C Hamano
2018-08-15 16:32 ` Duy Nguyen
2018-08-15 18:28 ` Junio C Hamano
2018-08-14 20:14 ` Jeff Hostetler
2018-08-12 8:15 ` [PATCH v4 3/5] unpack-trees: optimize walking same trees with cache-tree Nguyễn Thái Ngọc Duy
2018-08-13 18:58 ` Ben Peart
2018-08-15 16:38 ` Duy Nguyen
2018-08-12 8:15 ` [PATCH v4 4/5] unpack-trees: reduce malloc in cache-tree walk Nguyễn Thái Ngọc Duy
2018-08-12 8:15 ` [PATCH v4 5/5] unpack-trees: reuse (still valid) cache-tree from src_index Nguyễn Thái Ngọc Duy
2018-08-13 15:48 ` Elijah Newren
2018-08-13 15:57 ` Duy Nguyen
2018-08-13 16:05 ` Ben Peart
2018-08-13 16:25 ` Duy Nguyen
2018-08-13 17:15 ` Ben Peart
2018-08-13 19:01 ` [PATCH v4 0/5] Speed up unpack_trees() Junio C Hamano
2018-08-14 19:19 ` Ben Peart
2018-08-18 14:41 ` [PATCH v5 0/7] " Nguyễn Thái Ngọc Duy
2018-08-18 14:41 ` [PATCH v5 1/7] trace.h: support nested performance tracing Nguyễn Thái Ngọc Duy
2018-08-18 14:41 ` [PATCH v5 2/7] unpack-trees: add " Nguyễn Thái Ngọc Duy
2018-08-18 14:41 ` [PATCH v5 3/7] unpack-trees: optimize walking same trees with cache-tree Nguyễn Thái Ngọc Duy
2018-08-20 12:43 ` Ben Peart
2018-08-18 14:41 ` [PATCH v5 4/7] unpack-trees: reduce malloc in cache-tree walk Nguyễn Thái Ngọc Duy
2018-08-18 14:41 ` [PATCH v5 5/7] unpack-trees: reuse (still valid) cache-tree from src_index Nguyễn Thái Ngọc Duy
2018-08-18 14:41 ` [PATCH v5 6/7] unpack-trees: add missing cache invalidation Nguyễn Thái Ngọc Duy
2018-08-18 14:41 ` [PATCH v5 7/7] cache-tree: verify valid cache-tree in the test suite Nguyễn Thái Ngọc Duy
2018-08-18 21:45 ` Elijah Newren
2018-08-18 22:01 ` [PATCH v5 0/7] Speed up unpack_trees() Elijah Newren
2018-08-19 5:09 ` Duy Nguyen
2018-08-25 12:18 ` [PATCH] Document update for nd/unpack-trees-with-cache-tree Nguyễn Thái Ngọc Duy
2018-08-25 12:31 ` Martin Ågren
2018-08-25 13:02 ` [PATCH v2] " Nguyễn Thái Ngọc Duy
2018-07-27 15:50 ` [PATCH v1 0/3] [RFC] Speeding up checkout (and merge, rebase, etc) Ben Peart
2018-07-26 16:35 ` Duy Nguyen
2018-07-24 5:54 ` Junio C Hamano
2018-07-24 15:13 ` Duy Nguyen
2018-07-24 21:21 ` Jeff King
2018-07-25 16:09 ` Ben Peart
2018-07-24 4:27 ` Jeff King
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