From: Patrick Steinhardt <ps@pks.im>
To: "René Scharfe" <l.s.r@web.de>
Cc: git@vger.kernel.org, "Jeff King" <peff@peff.net>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"Junio C Hamano" <gitster@pobox.com>
Subject: Re: [PATCH 3/6] connected: refactor iterator to return next object ID directly
Date: Mon, 23 Aug 2021 08:47:54 +0200 [thread overview]
Message-ID: <YSNEmsO1ZIQXHs6X@ncase> (raw)
In-Reply-To: <5f9e7a4f-d95b-4242-1add-7b20057293a3@web.de>
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On Fri, Aug 20, 2021 at 07:43:06PM +0200, René Scharfe wrote:
> Am 20.08.21 um 12:08 schrieb Patrick Steinhardt:
> > The object ID iterator used by the connectivity checks returns the next
> > object ID via an out-parameter and then uses a return code to indicate
> > whether an item was found. This is a bit roundabout: instead of a
> > separate error code, we can just retrun the next object ID directly and
>
> s/retrun/return/
>
> > use `NULL` pointers as indicator that the iterator got no items left.
> > Furthermore, this avoids a copy of the object ID.
> >
> > Refactor the iterator and all its implementations to return object IDs
> > directly. While I was honestly hoping for a small speedup given that we
> > can now avoid a copy, both versions perform the same. Still, the end
> > result is easier to understand and thus it makes sense to keep this
> > refactoring regardless.
>
> check_connected() calls find_pack_entry_one() on the object ID hash,
> which copies it anyway. Perhaps that and caching prevent the expected
> speedup?
>
> The private copy made sure check_connected() could not modify the
> object IDs. It still only reads them with this patch, but the compiler
> no longer prevents writes. The iterators could return const pointers
> to restore that guarantee.
Right, will change the signature and re-benchmark. I'd be surprised if
it significantly changed the picture, but let's see.
Patrick
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next prev parent reply other threads:[~2021-08-23 6:48 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-20 10:08 [PATCH 0/6] Speed up mirror-fetches with many refs Patrick Steinhardt
2021-08-20 10:08 ` [PATCH 1/6] fetch: speed up lookup of want refs via commit-graph Patrick Steinhardt
2021-08-20 14:27 ` Derrick Stolee
2021-08-20 17:18 ` Junio C Hamano
2021-08-23 6:46 ` Patrick Steinhardt
2021-08-25 14:12 ` Derrick Stolee
2021-08-20 10:08 ` [PATCH 2/6] fetch: avoid unpacking headers in object existence check Patrick Steinhardt
2021-08-25 23:44 ` Ævar Arnfjörð Bjarmason
2021-08-20 10:08 ` [PATCH 3/6] connected: refactor iterator to return next object ID directly Patrick Steinhardt
2021-08-20 14:32 ` Derrick Stolee
2021-08-20 17:43 ` Junio C Hamano
2021-08-20 17:43 ` René Scharfe
2021-08-23 6:47 ` Patrick Steinhardt [this message]
2021-08-20 10:08 ` [PATCH 4/6] fetch-pack: optimize loading of refs via commit graph Patrick Steinhardt
2021-08-20 14:37 ` Derrick Stolee
2021-08-20 10:08 ` [PATCH 5/6] fetch: refactor fetch refs to be more extendable Patrick Steinhardt
2021-08-20 14:41 ` Derrick Stolee
2021-08-20 10:08 ` [PATCH 6/6] fetch: avoid second connectivity check if we already have all objects Patrick Steinhardt
2021-08-20 14:47 ` Derrick Stolee
2021-08-23 6:52 ` Patrick Steinhardt
2021-08-20 14:50 ` [PATCH 0/6] Speed up mirror-fetches with many refs Derrick Stolee
2021-08-21 0:09 ` Junio C Hamano
2021-08-24 10:36 ` [PATCH v2 0/7] " Patrick Steinhardt
2021-08-24 10:36 ` [PATCH v2 1/7] fetch: speed up lookup of want refs via commit-graph Patrick Steinhardt
2021-08-25 14:16 ` Derrick Stolee
2021-08-24 10:37 ` [PATCH v2 2/7] fetch: avoid unpacking headers in object existence check Patrick Steinhardt
2021-08-24 10:37 ` [PATCH v2 3/7] connected: refactor iterator to return next object ID directly Patrick Steinhardt
2021-08-24 10:37 ` [PATCH v2 4/7] fetch-pack: optimize loading of refs via commit graph Patrick Steinhardt
2021-08-24 10:37 ` [PATCH v2 5/7] fetch: refactor fetch refs to be more extendable Patrick Steinhardt
2021-08-25 14:19 ` Derrick Stolee
2021-09-01 12:48 ` Patrick Steinhardt
2021-08-24 10:37 ` [PATCH v2 6/7] fetch: merge fetching and consuming refs Patrick Steinhardt
2021-08-25 14:26 ` Derrick Stolee
2021-09-01 12:49 ` Patrick Steinhardt
2021-08-24 10:37 ` [PATCH v2 7/7] fetch: avoid second connectivity check if we already have all objects Patrick Steinhardt
2021-08-24 22:48 ` [PATCH v2 0/7] Speed up mirror-fetches with many refs Junio C Hamano
2021-08-25 6:04 ` Patrick Steinhardt
2021-08-25 14:27 ` Derrick Stolee
2021-09-01 13:09 ` [PATCH v3 " Patrick Steinhardt
2021-09-01 13:09 ` [PATCH v3 1/7] fetch: speed up lookup of want refs via commit-graph Patrick Steinhardt
2021-09-01 13:09 ` [PATCH v3 2/7] fetch: avoid unpacking headers in object existence check Patrick Steinhardt
2021-09-01 13:09 ` [PATCH v3 3/7] connected: refactor iterator to return next object ID directly Patrick Steinhardt
2021-09-01 13:09 ` [PATCH v3 4/7] fetch-pack: optimize loading of refs via commit graph Patrick Steinhardt
2021-09-01 13:09 ` [PATCH v3 5/7] fetch: refactor fetch refs to be more extendable Patrick Steinhardt
2021-09-01 13:10 ` [PATCH v3 6/7] fetch: merge fetching and consuming refs Patrick Steinhardt
2021-09-01 13:10 ` [PATCH v3 7/7] fetch: avoid second connectivity check if we already have all objects Patrick Steinhardt
2021-09-01 19:58 ` [PATCH v3 0/7] Speed up mirror-fetches with many refs Junio C Hamano
2021-09-08 0:08 ` Junio C Hamano
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