From: Junio C Hamano <gitster@pobox.com>
To: Jonathan Tan <jonathantanmy@google.com>
Cc: git@vger.kernel.org, sluongng@gmail.com
Subject: Re: [PATCH 2/2] pack-objects: prefetch objects to be packed
Date: Wed, 22 Jul 2020 14:45:44 -0700 [thread overview]
Message-ID: <xmqqo8o7441j.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <20200722213048.1581991-1-jonathantanmy@google.com> (Jonathan Tan's message of "Wed, 22 Jul 2020 14:30:48 -0700")
Jonathan Tan <jonathantanmy@google.com> writes:
> OK - how about:
>
> [start]
> When an object to be packed is noticed to be missing, prefetch all
> to-be-packed objects in one batch.
>
> Most of the time (typically, when serving a fetch or when pushing),
> packs consist only of objects that the repo has. To maintain the
> performance in this case, the existing object type read is made to also
> serve as the object existence check: if the read fails, then we do the
> prefetch.
>
> An alternative design is to loop over all the entries in to_pack,
> checking the existence of each object, and prefetching if we notice any
> missing. This would result in clearer code, but would incur some
> performance degradation in the aforementioned most common case due to
> the additional object existence checks.
>
> Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
> [end]
>
> The first paragraph is already in the original, and the rest are
> additions.
Sure.
The first two paragraphs would be sufficient, although the last
paragraph wouldn't hurt.
prev parent reply other threads:[~2020-07-22 21:45 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-21 0:21 [PATCH 0/2] Prefetch objects in pack-objects Jonathan Tan
2020-07-21 0:21 ` [PATCH 1/2] pack-objects: refactor to oid_object_info_extended Jonathan Tan
2020-07-21 0:21 ` [PATCH 2/2] pack-objects: prefetch objects to be packed Jonathan Tan
2020-07-21 1:00 ` Junio C Hamano
2020-07-21 16:37 ` Jonathan Tan
2020-07-21 19:23 ` Junio C Hamano
2020-07-21 21:27 ` Junio C Hamano
2020-07-21 23:37 ` Jonathan Tan
2020-07-21 23:56 ` Junio C Hamano
2020-07-21 23:20 ` Jonathan Tan
2020-07-21 23:51 ` Junio C Hamano
2020-07-22 21:30 ` Jonathan Tan
2020-07-22 21:45 ` Junio C Hamano [this message]
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