From: Ben Peart <peartben@gmail.com>
To: "Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>
Cc: Ben.Peart@microsoft.com, git@vger.kernel.org, gitster@pobox.com,
peff@peff.net
Subject: Re: [PATCH v2 0/4] Speed up unpack_trees()
Date: Mon, 30 Jul 2018 14:10:34 -0400 [thread overview]
Message-ID: <9a9a309c-7143-e642-cfd8-6df76e77995a@gmail.com> (raw)
In-Reply-To: <20180729103306.16403-1-pclouds@gmail.com>
On 7/29/2018 6:33 AM, Nguyễn Thái Ngọc Duy wrote:
> This series speeds up unpack_trees() a bit by using cache-tree.
> unpack-trees could bit split in three big parts
>
> - the actual tree unpacking and running n-way merging
> - update worktree, which could be expensive depending on how much I/O
> is involved
> - repair cache-tree
>
> This series focuses on the first part alone and could give 700%
> speedup (best case possible scenario, real life ones probably not that
> impressive).
>
> It also shows that the reparing cache-tree is kinda expensive. I have
> an idea of reusing cache-tree from the original index, but I'll leave
> that to Ben or others to try out and see if it helps at all.
>
> v2 fixes the comments from Junio, adds more performance tracing and
> reduces the cost of adding index entries.
>
> Nguyễn Thái Ngọc Duy (4):
> unpack-trees.c: add performance tracing
> unpack-trees: optimize walking same trees with cache-tree
> unpack-trees: reduce malloc in cache-tree walk
> unpack-trees: cheaper index update when walking by cache-tree
>
> cache-tree.c | 2 +
> cache.h | 1 +
> read-cache.c | 3 +-
> unpack-trees.c | 161 ++++++++++++++++++++++++++++++++++++++++++++++++-
> unpack-trees.h | 1 +
> 5 files changed, 166 insertions(+), 2 deletions(-)
>
I ran "git checkout" on a large repo and averaged the results of 3 runs.
This clearly demonstrates the benefit of the optimized unpack_trees()
as even the final "diff-index" is essentially a 3rd call to unpack_trees().
baseline new
----------------------------------------------------------------------
0.535510167 0.556558733 s: read cache .git/index
0.3057373 0.3147105 s: initialize name hash
0.0184082 0.023558433 s: preload index
0.086910967 0.089085967 s: refresh index
7.889590767 2.191554433 s: unpack trees
0.120760833 0.131941267 s: update worktree after a merge
2.2583504 2.572663167 s: repair cache-tree
0.8916137 0.959495233 s: write index, changed mask = 28
3.405199233 0.2710663 s: unpack trees
0.000999667 0.0021554 s: update worktree after a merge
3.4063306 0.273318333 s: diff-index
16.9524923 9.462943133 s: git command:
'c:\git-sdk-64\usr\src\git\git.exe' checkout
The first call to unpack_trees() saves 72%
The 2nd and 3rd call save 92%
Total time savings for the entire command was 44%
In the performance game of whack-a-mole, that call to repair cache-tree
is now looking quite expensive...
Ben
next prev parent reply other threads:[~2018-07-30 18:10 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
2018-08-10 19:48 ` Duy Nguyen
2018-07-30 18:10 ` Ben Peart [this message]
2018-07-31 15:31 ` [PATCH v2 0/4] Speed up unpack_trees() 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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