From: Jeff King <peff@peff.net>
To: Jonathan Nieder <jrnieder@gmail.com>
Cc: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
git@vger.kernel.org, "Junio C Hamano" <gitster@pobox.com>,
"Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>,
"Michael Haggerty" <mhagger@alum.mit.edu>,
"Stefan Beller" <stefanbeller@gmail.com>,
"Matt McCutchen" <matt@mattmccutchen.net>
Subject: Re: [PATCH 4/4] gc docs: downplay the usefulness of --aggressive
Date: Mon, 18 Mar 2019 17:22:27 -0400 [thread overview]
Message-ID: <20190318212227.GD29661@sigill.intra.peff.net> (raw)
In-Reply-To: <20190318202824.GA24222@gmail.com>
On Mon, Mar 18, 2019 at 01:28:24PM -0700, Jonathan Nieder wrote:
> > +Using this option may optimize for disk space at the expense of
> > +runtime performance. See the `--depth` and `--window` documentation in
> > +linkgit:git-repack[1]. It is not recommended that this option be used
> > +to improve performance for a given repository without running tailored
> > +performance benchmarks on it. It may make things better, or worse. Not
> > +using this at all is the right trade-off for most users and their
> > +repositories.
>
> This part kind of feels like giving up. Can we make --aggressive have
> good runtime read performance so we don't have to hedge this way?
> E.g. is this patch papering over a poor choice of --depth setting in
> --aggressive?
I thought we already did that, in 07e7dbf0db (gc: default aggressive
depth to 50, 2016-08-11). As far as I know, "--aggressive" produces
packs with similar runtime performance.
It is possible, if it finds more deltas due to the larger window, that
we'd spend more time accessing those deltas. But if the chains aren't
long, the base cache tends to perform well, and delta reconstruction is
about the same cost as zlib inflating. And we have a smaller disk cache
footprint.
-Peff
next prev parent reply other threads:[~2019-03-18 21:22 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-18 16:14 [PATCH 0/4] gc docs: modernize and fix the documentation Ævar Arnfjörð Bjarmason
2019-03-18 16:14 ` [PATCH 1/4] gc docs: modernize the advice for manually running "gc" Ævar Arnfjörð Bjarmason
2019-03-18 21:27 ` Jeff King
2019-03-18 22:18 ` Ævar Arnfjörð Bjarmason
2019-03-18 16:15 ` [PATCH 2/4] gc docs: include the "gc.*" section from "config" in "gc" Ævar Arnfjörð Bjarmason
2019-03-18 21:31 ` Jeff King
2019-03-21 22:11 ` Andreas Heiduk
2019-03-19 2:08 ` Duy Nguyen
2019-03-18 16:15 ` [PATCH 3/4] gc docs: de-duplicate "OPTIONS" and "CONFIGURATION" Ævar Arnfjörð Bjarmason
2019-03-18 21:49 ` Jeff King
2019-03-18 22:48 ` Ævar Arnfjörð Bjarmason
2019-03-18 23:42 ` Jeff King
2019-03-18 16:15 ` [PATCH 4/4] gc docs: downplay the usefulness of --aggressive Ævar Arnfjörð Bjarmason
2019-03-18 20:28 ` Jonathan Nieder
2019-03-18 21:22 ` Jeff King [this message]
2019-03-18 22:13 ` Ævar Arnfjörð Bjarmason
2019-03-18 23:53 ` Jeff King
2019-03-19 6:54 ` Johannes Sixt
2019-03-19 9:28 ` Ævar Arnfjörð Bjarmason
2019-03-18 21:51 ` [PATCH 0/4] gc docs: modernize and fix the documentation Jeff King
2019-03-18 22:45 ` Ævar Arnfjörð Bjarmason
2019-03-19 0:18 ` Jeff King
2019-05-06 9:44 ` Ævar Arnfjörð Bjarmason
2019-05-07 7:51 ` Jeff King
2019-05-09 23:20 ` Ævar Arnfjörð Bjarmason
2019-07-31 4:26 ` Jeff King
2019-07-31 10:12 ` Ævar Arnfjörð Bjarmason
2019-03-21 20:50 ` [PATCH v2 00/10] " Ævar Arnfjörð Bjarmason
2019-03-22 9:32 ` [PATCH v3 00/11] gc docs: modernize the advice for manually running "gc" Ævar Arnfjörð Bjarmason
2019-03-22 9:32 ` [PATCH v3 01/11] " Ævar Arnfjörð Bjarmason
2019-03-22 9:32 ` [PATCH v3 02/11] gc docs: stop noting "repack" flags Ævar Arnfjörð Bjarmason
2019-03-22 9:32 ` [PATCH v3 03/11] gc docs: clean grammar for "gc.bigPackThreshold" Ævar Arnfjörð Bjarmason
2019-03-22 9:32 ` [PATCH v3 04/11] gc docs: include the "gc.*" section from "config" in "gc" Ævar Arnfjörð Bjarmason
2019-03-30 18:04 ` Todd Zullinger
2019-04-07 19:52 ` [PATCH v4 00/11] gc docs: modernize and fix the documentation Ævar Arnfjörð Bjarmason
2019-04-07 19:52 ` [PATCH v4 01/11] gc docs: modernize the advice for manually running "gc" Ævar Arnfjörð Bjarmason
2019-04-07 19:52 ` [PATCH v4 02/11] gc docs: stop noting "repack" flags Ævar Arnfjörð Bjarmason
2019-04-07 19:52 ` [PATCH v4 03/11] gc docs: clean grammar for "gc.bigPackThreshold" Ævar Arnfjörð Bjarmason
2019-04-07 19:52 ` [PATCH v4 04/11] gc docs: include the "gc.*" section from "config" in "gc" Ævar Arnfjörð Bjarmason
2019-04-07 19:52 ` [PATCH v4 05/11] gc docs: re-flow the "gc.*" section in "config" Ævar Arnfjörð Bjarmason
2019-04-07 19:52 ` [PATCH v4 06/11] gc docs: fix formatting for "gc.writeCommitGraph" Ævar Arnfjörð Bjarmason
2019-04-07 19:52 ` [PATCH v4 07/11] gc docs: note how --aggressive impacts --window & --depth Ævar Arnfjörð Bjarmason
2019-04-07 19:52 ` [PATCH v4 08/11] gc docs: downplay the usefulness of --aggressive Ævar Arnfjörð Bjarmason
2019-04-07 19:52 ` [PATCH v4 09/11] gc docs: note "gc --aggressive" in "fast-import" Ævar Arnfjörð Bjarmason
2019-04-07 19:52 ` [PATCH v4 10/11] gc docs: clarify that "gc" doesn't throw away referenced objects Ævar Arnfjörð Bjarmason
2019-04-07 19:52 ` [PATCH v4 11/11] gc docs: remove incorrect reference to gc.auto=0 Ævar Arnfjörð Bjarmason
2019-03-22 9:32 ` [PATCH v3 05/11] gc docs: re-flow the "gc.*" section in "config" Ævar Arnfjörð Bjarmason
2019-03-22 9:32 ` [PATCH v3 06/11] gc docs: fix formatting for "gc.writeCommitGraph" Ævar Arnfjörð Bjarmason
2019-03-22 9:32 ` [PATCH v3 07/11] gc docs: note how --aggressive impacts --window & --depth Ævar Arnfjörð Bjarmason
2019-03-22 9:32 ` [PATCH v3 08/11] gc docs: downplay the usefulness of --aggressive Ævar Arnfjörð Bjarmason
2019-03-22 9:32 ` [PATCH v3 09/11] gc docs: note "gc --aggressive" in "fast-import" Ævar Arnfjörð Bjarmason
2019-03-22 9:32 ` [PATCH v3 10/11] gc docs: clarify that "gc" doesn't throw away referenced objects Ævar Arnfjörð Bjarmason
2019-03-22 9:32 ` [PATCH v3 11/11] gc docs: remove incorrect reference to gc.auto=0 Ævar Arnfjörð Bjarmason
2019-03-21 20:50 ` [PATCH v2 01/10] gc docs: modernize the advice for manually running "gc" Ævar Arnfjörð Bjarmason
2019-03-22 6:01 ` Junio C Hamano
2019-03-21 20:50 ` [PATCH v2 02/10] gc docs: stop noting "repack" flags Ævar Arnfjörð Bjarmason
2019-03-21 20:50 ` [PATCH v2 03/10] gc docs: clean grammar for "gc.bigPackThreshold" Ævar Arnfjörð Bjarmason
2019-03-21 20:50 ` [PATCH v2 04/10] gc docs: include the "gc.*" section from "config" in "gc" Ævar Arnfjörð Bjarmason
2019-03-21 20:50 ` [PATCH v2 05/10] gc docs: re-flow the "gc.*" section in "config" Ævar Arnfjörð Bjarmason
2019-03-21 20:50 ` [PATCH v2 06/10] gc docs: note how --aggressive impacts --window & --depth Ævar Arnfjörð Bjarmason
2019-03-21 20:50 ` [PATCH v2 07/10] gc docs: downplay the usefulness of --aggressive Ævar Arnfjörð Bjarmason
2019-03-21 20:50 ` [PATCH v2 08/10] gc docs: note "gc --aggressive" in "fast-import" Ævar Arnfjörð Bjarmason
2019-03-21 20:50 ` [PATCH v2 09/10] gc docs: clarify that "gc" doesn't throw away referenced objects Ævar Arnfjörð Bjarmason
2019-03-21 20:50 ` [PATCH v2 10/10] gc docs: remove incorrect reference to gc.auto=0 Ævar Arnfjörð Bjarmason
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