From: Han-Wen Nienhuys <hanwenn@gmail.com>
To: Patrick Steinhardt <ps@pks.im>
Cc: git@vger.kernel.org, Jonathan Nieder <jrnieder@gmail.com>
Subject: Re: [PATCH 7/8] reftable/merged: reuse buffer to compute record keys
Date: Thu, 21 Dec 2023 11:48:50 +0100 [thread overview]
Message-ID: <CAOw_e7Yps5T32cAZrKO2meebEsdo4h6AWoFF3A4PCqF9AHuNxQ@mail.gmail.com> (raw)
In-Reply-To: <23c060d1e21573581ca6c5db50ca756b61078e3e.1700549493.git.ps@pks.im>
On Tue, Nov 21, 2023 at 8:07 AM Patrick Steinhardt <ps@pks.im> wrote:
>
> When iterating over entries in the merged iterator's queue, we compute
> the key of each of the entries and write it into a buffer. We do not
> reuse the buffer though and thus re-allocate it on every iteration,
> which is wasteful given that we never transfer ownership of the
> allocated bytes outside of the loop.
>
From a brief read, change looks good.
In the C code, each key has to pass through the pqueue which is
(assuming auto-compaction) has log2(#tables) entries. The JGit code
assumes that the base table will be very large and the rest small.
This means that most keys come from the base table, and has some
special casing so those keys don't have to pass through the pqueue. If
you worry about efficiency, this might be something to look into.
--
Han-Wen Nienhuys - hanwenn@gmail.com - http://www.xs4all.nl/~hanwen
next prev parent reply other threads:[~2023-12-21 10:49 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-21 7:04 [PATCH 0/8] reftable: small set of fixes Patrick Steinhardt
2023-11-21 7:04 ` [PATCH 1/8] reftable: wrap EXPECT macros in do/while Patrick Steinhardt
2023-11-21 7:04 ` [PATCH 2/8] reftable: handle interrupted reads Patrick Steinhardt
2023-11-21 7:04 ` [PATCH 3/8] reftable: handle interrupted writes Patrick Steinhardt
2023-11-21 7:04 ` [PATCH 4/8] reftable/stack: verify that `reftable_stack_add()` uses auto-compaction Patrick Steinhardt
2023-11-21 7:04 ` [PATCH 5/8] reftable/stack: perform auto-compaction with transactional interface Patrick Steinhardt
2023-12-21 10:29 ` Han-Wen Nienhuys
2023-12-21 10:45 ` Patrick Steinhardt
2023-11-21 7:04 ` [PATCH 6/8] reftable/stack: reuse buffers when reloading stack Patrick Steinhardt
2023-11-21 7:04 ` [PATCH 7/8] reftable/merged: reuse buffer to compute record keys Patrick Steinhardt
2023-12-21 10:48 ` Han-Wen Nienhuys [this message]
2023-11-21 7:04 ` [PATCH 8/8] reftable/stack: fix stale lock when dying Patrick Steinhardt
2023-12-08 14:52 ` [PATCH v2 00/11] reftable: small set of fixes Patrick Steinhardt
2023-12-08 14:52 ` [PATCH v2 01/11] reftable: wrap EXPECT macros in do/while Patrick Steinhardt
2023-12-08 14:53 ` [PATCH v2 02/11] reftable: handle interrupted reads Patrick Steinhardt
2023-12-08 21:30 ` Taylor Blau
2023-12-11 9:08 ` Patrick Steinhardt
2023-12-08 14:53 ` [PATCH v2 03/11] reftable: handle interrupted writes Patrick Steinhardt
2023-12-08 14:53 ` [PATCH v2 04/11] reftable/stack: verify that `reftable_stack_add()` uses auto-compaction Patrick Steinhardt
2023-12-08 21:35 ` Taylor Blau
2023-12-08 23:46 ` Eric Sunshine
2023-12-11 9:08 ` Patrick Steinhardt
2023-12-11 9:36 ` Eric Sunshine
2023-12-08 14:53 ` [PATCH v2 05/11] reftable/stack: perform auto-compaction with transactional interface Patrick Steinhardt
2023-12-08 22:14 ` Taylor Blau
2023-12-11 9:08 ` Patrick Steinhardt
2023-12-08 14:53 ` [PATCH v2 06/11] reftable/stack: reuse buffers when reloading stack Patrick Steinhardt
2023-12-08 22:17 ` Taylor Blau
2023-12-11 9:08 ` Patrick Steinhardt
2023-12-21 10:58 ` Han-Wen Nienhuys
2023-12-08 14:53 ` [PATCH v2 07/11] reftable/stack: fix stale lock when dying Patrick Steinhardt
2023-12-08 22:24 ` Taylor Blau
2023-12-11 9:08 ` Patrick Steinhardt
2023-12-08 14:53 ` [PATCH v2 08/11] reftable/stack: fix use of unseeded randomness Patrick Steinhardt
2023-12-21 10:49 ` Han-Wen Nienhuys
2023-12-08 14:53 ` [PATCH v2 09/11] reftable/merged: reuse buffer to compute record keys Patrick Steinhardt
2023-12-08 14:53 ` [PATCH v2 10/11] reftable/block: introduce macro to initialize `struct block_iter` Patrick Steinhardt
2023-12-08 14:53 ` [PATCH v2 11/11] reftable/block: reuse buffer to compute record keys Patrick Steinhardt
2023-12-21 10:43 ` Han-Wen Nienhuys
2023-12-28 5:53 ` Patrick Steinhardt
2023-12-08 22:26 ` [PATCH v2 00/11] reftable: small set of fixes Taylor Blau
2023-12-11 9:07 ` [PATCH v3 " Patrick Steinhardt
2023-12-11 9:07 ` [PATCH v3 01/11] reftable: wrap EXPECT macros in do/while Patrick Steinhardt
2023-12-11 9:07 ` [PATCH v3 02/11] reftable: handle interrupted reads Patrick Steinhardt
2023-12-11 9:07 ` [PATCH v3 03/11] reftable: handle interrupted writes Patrick Steinhardt
2023-12-11 9:07 ` [PATCH v3 04/11] reftable/stack: verify that `reftable_stack_add()` uses auto-compaction Patrick Steinhardt
2023-12-11 20:15 ` Taylor Blau
2023-12-12 3:44 ` Patrick Steinhardt
2023-12-11 9:07 ` [PATCH v3 05/11] reftable/stack: perform auto-compaction with transactional interface Patrick Steinhardt
2023-12-11 9:07 ` [PATCH v3 06/11] reftable/stack: reuse buffers when reloading stack Patrick Steinhardt
2023-12-11 9:07 ` [PATCH v3 07/11] reftable/stack: fix stale lock when dying Patrick Steinhardt
2023-12-11 9:07 ` [PATCH v3 08/11] reftable/stack: fix use of unseeded randomness Patrick Steinhardt
2023-12-11 9:08 ` [PATCH v3 09/11] reftable/merged: reuse buffer to compute record keys Patrick Steinhardt
2023-12-11 9:08 ` [PATCH v3 10/11] reftable/block: introduce macro to initialize `struct block_iter` Patrick Steinhardt
2023-12-11 9:08 ` [PATCH v3 11/11] reftable/block: reuse buffer to compute record keys Patrick Steinhardt
2023-12-11 20:16 ` [PATCH v3 00/11] reftable: small set of fixes Taylor Blau
2023-12-12 3:45 ` Patrick Steinhardt
2023-12-21 11:08 ` [PATCH 0/8] " Han-Wen Nienhuys
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