From: Duy Nguyen <pclouds@gmail.com>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: git <git@vger.kernel.org>, Ben Peart <benpeart@microsoft.com>,
Alex Vandiver <alexmv@dropbox.com>,
Christian Couder <christian.couder@gmail.com>,
David Turner <dturner@twopensource.com>
Subject: Re: Some rough edges of core.fsmonitor
Date: Sat, 27 Jan 2018 08:36:19 +0700 [thread overview]
Message-ID: <CACsJy8BpO0s6facg+zcKC9icijpefkipM326n6xOArjn=ZW6+w@mail.gmail.com> (raw)
In-Reply-To: <87efmcw3fa.fsf@evledraar.gmail.com>
On Sat, Jan 27, 2018 at 7:28 AM, Ævar Arnfjörð Bjarmason
<avarab@gmail.com> wrote:
> 3) A lot of time spend reading the index (or something..)
I'm resending a patch from my old index-helper series. It should
measure all big time consuming blocks in git. Maybe we should get it
merged...
> While the hook itself takes ~20ms (and watchman itself 1/4 of that)
> status as a whole takes much longer. gprof reveals:
>
> Each sample counts as 0.01 seconds.
> % cumulative self self total
> time seconds seconds calls ms/call ms/call name
> 15.38 0.02 0.02 221690 0.00 0.00 memihash
This sounds like name-hash to me.
> 15.38 0.04 0.02 221689 0.00 0.00 create_from_disk
> 7.69 0.05 0.01 2216897 0.00 0.00 git_bswap32
> 7.69 0.06 0.01 222661 0.00 0.00 ce_path_match
> 7.69 0.07 0.01 221769 0.00 0.00 hashmap_add
> 7.69 0.08 0.01 39941 0.00 0.00 prep_exclude
> 7.69 0.09 0.01 39940 0.00 0.00 strbuf_addch
> 7.69 0.10 0.01 1 10.00 10.00 read_one
> 7.69 0.11 0.01 1 10.00 10.00 refresh_index
> 7.69 0.12 0.01 1 10.00 10.00 tweak_fsmonitor
> 7.69 0.13 0.01 preload_thread
>
> The index is 24M in this case, I guess it's unpacking it, but I wonder
> if this couldn't be much faster if we saved away the result of the last
> "status" in something that's quick to access, and then if nothing
No we could do better, we could cache parsed index content so
everybody benefits. I demonstrated it with my "index v254" patch a
while back:
https://public-inbox.org/git/1399980019-8706-1-git-send-email-pclouds@gmail.com/
With the patch I'm sending soon, we can see how much time reading an
index take out of that ~140-150ms (and we probably can cut down index
read time to like 10-20% when cached).
> changed we just report that, and no need to re-write the index (or just
> write the "it was clean at this time" part).
Hmm.. does an index write increase that much time?
--
Duy
next prev parent reply other threads:[~2018-01-27 1:36 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-27 0:28 Some rough edges of core.fsmonitor Ævar Arnfjörð Bjarmason
2018-01-27 1:36 ` Duy Nguyen [this message]
2018-01-27 1:39 ` [PATCH] trace: measure where the time is spent in the index-heavy operations Nguyễn Thái Ngọc Duy
2018-01-27 11:58 ` Thomas Gummerer
2018-01-27 12:27 ` [PATCH v2] " Nguyễn Thái Ngọc Duy
2018-01-27 11:43 ` Some rough edges of core.fsmonitor Ævar Arnfjörð Bjarmason
2018-01-27 12:39 ` Duy Nguyen
2018-01-27 13:09 ` Duy Nguyen
2018-01-27 19:01 ` Ævar Arnfjörð Bjarmason
2018-01-30 22:41 ` Ben Peart
2018-01-29 9:40 ` Duy Nguyen
2018-01-29 23:16 ` Ben Peart
2018-02-01 10:40 ` Duy Nguyen
2018-01-28 20:44 ` Johannes Schindelin
2018-01-28 22:28 ` Ævar Arnfjörð Bjarmason
2018-01-30 1:21 ` Ben Peart
2018-01-31 10:15 ` Duy Nguyen
2018-02-04 9:38 ` [PATCH] dir.c: ignore paths containing .git when invalidating untracked cache Nguyễn Thái Ngọc Duy
2018-02-05 17:44 ` Ben Peart
2018-02-06 12:02 ` Duy Nguyen
2018-02-07 9:21 ` [PATCH v2] " Nguyễn Thái Ngọc Duy
2018-02-07 9:21 ` Nguyễn Thái Ngọc Duy
2018-02-07 16:59 ` Ben Peart
2018-02-13 10:00 ` Duy Nguyen
2018-02-13 17:57 ` Junio C Hamano
2018-02-14 1:24 ` Duy Nguyen
2018-02-14 8:00 ` Junio C Hamano
2018-01-30 22:57 ` Some rough edges of core.fsmonitor Ben Peart
2018-01-30 23:16 ` Ævar Arnfjörð Bjarmason
2018-01-31 16:12 ` Ben Peart
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