From: "SZEDER Gábor" <szeder.dev@gmail.com>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>,
Jeff King <peff@peff.net>
Subject: Re: [PATCH 3/5] cocci: make "coccicheck" rule incremental
Date: Thu, 25 Aug 2022 21:44:18 +0200 [thread overview]
Message-ID: <20220825194418.GI1735@szeder.dev> (raw)
In-Reply-To: <patch-3.5-6fa83695f1f-20220825T141212Z-avarab@gmail.com>
On Thu, Aug 25, 2022 at 04:36:15PM +0200, Ævar Arnfjörð Bjarmason wrote:
> * Since we create a single "*.cocci.patch+" we don't know where to
> pick up where we left off. Note that (per [1]) we've had a race
> condition since 960154b9c17 (coccicheck: optionally batch spatch
> invocations, 2019-05-06) which might result in us producing corrupt
> patches to to the concurrent appending to "$@+" in the pre-image.
>
> That bug is now fixed.
There is no bug, because there is no concurrent appending to "$@+".
The message you mention seems to be irrelevant, as it talks about
'xargs -P', but the invocation in '%.cocci.patch' targets never used
'-P'.
> Which is why we'll not depend on $(FOUND_H_SOURCES) but the *.o file
> corresponding to the *.c file, if it exists already. This means that
> we can do:
>
> make all
> make coccicheck
> make -W column.h coccicheck
>
> By depending on the *.o we piggy-back on
> COMPUTE_HEADER_DEPENDENCIES. See c234e8a0ecf (Makefile: make the
> "sparse" target non-.PHONY, 2021-09-23) for prior art of doing that
> for the *.sp files. E.g.:
>
> make contrib/coccinelle/free.cocci.patch
> make -W column.h contrib/coccinelle/free.cocci.patch
>
> Will take around 15 seconds for the second command on my 8 core box if
> I didn't run "make" beforehand to create the *.o files. But around 2
> seconds if I did and we have those "*.o" files.
>
> Notes about the approach of piggy-backing on *.o for dependencies:
>
> * It *is* a trade-off since we'll pay the extra cost of running the C
> compiler, but we're probably doing that anyway.
This assumption doesn't hold, and I very much dislike the idea of
depending on *.o files:
- Our static-analysis CI job doesn't build Git, now it will have to.
- I don't have Coccinelle installed, because my distro doesn't ship
it, and though the previous release did ship it, it was outdated.
Instead I use Coccinelle's most recent version from a container
which doesn't contain any build tools apart from 'make' for 'make
coccicheck'.
With this patch series I can't use this containerized Coccinelle
at all, because even though I've already built git on the host,
the dependency on *.o files triggers a BUILD-OPTIONS check during
'make coccicheck', and due to the missing 'curl-config' the build
options do differ, triggering a rebuild, which in the absence of a
compiler fails.
And then the next 'make' on the host will have to rebuild
everything again...
> * We can take better advantage of parallelism, while making sure that
> we don't racily append to the contrib/coccinelle/swap.cocci.patch
> file from multiple workers.
>
> Before this change running "make coccicheck" would by default end
> up pegging just one CPU at the very end for a while, usually as
> we'd finish whichever *.cocci rule was the most expensive.
>
> This could be mitigated by combining "make -jN" with
> SPATCH_BATCH_SIZE, see 960154b9c17 (coccicheck: optionally batch
> spatch invocations, 2019-05-06). But doing so required careful
> juggling, as e.g. setting both to 4 would yield 16 workers.
No, setting both to 4 does yield 4 workers.
SPATCH_BATCH_SIZE has nothing to do with parallelism; it is merely the
number of C source files that we pass to a single 'spatch' invocation,
but for any given semantic patch it's still a sequential loop.
next prev parent reply other threads:[~2022-08-25 19:44 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-25 14:36 [PATCH 0/5] cocci: make "incremental" possible + a ccache-like tool Ævar Arnfjörð Bjarmason
2022-08-25 14:36 ` [PATCH 1/5] Makefile: add ability to TAB-complete cocci *.patch rules Ævar Arnfjörð Bjarmason
2022-08-25 14:36 ` [PATCH 2/5] Makefile: have "coccicheck" re-run if flags change Ævar Arnfjörð Bjarmason
2022-08-25 15:29 ` SZEDER Gábor
2022-08-25 14:36 ` [PATCH 3/5] cocci: make "coccicheck" rule incremental Ævar Arnfjörð Bjarmason
2022-08-25 19:44 ` SZEDER Gábor [this message]
2022-08-25 22:18 ` Ævar Arnfjörð Bjarmason
2022-08-26 10:43 ` SZEDER Gábor
2022-08-25 14:36 ` [PATCH 4/5] cocci: make incremental compilation even faster Ævar Arnfjörð Bjarmason
2022-08-25 14:36 ` [PATCH 5/5] spatchcache: add a ccache-alike for "spatch" Ævar Arnfjörð Bjarmason
2022-08-31 20:57 ` [PATCH v2 0/9] cocci: make "incremental" possible + a ccache-like tool Ævar Arnfjörð Bjarmason
2022-08-31 20:57 ` [PATCH v2 1/9] cocci rules: remove unused "F" metavariable from pending rule Ævar Arnfjörð Bjarmason
2022-08-31 20:57 ` [PATCH v2 2/9] Makefile: add ability to TAB-complete cocci *.patch rules Ævar Arnfjörð Bjarmason
2022-08-31 20:57 ` [PATCH v2 3/9] Makefile: have "coccicheck" re-run if flags change Ævar Arnfjörð Bjarmason
2022-08-31 20:57 ` [PATCH v2 4/9] Makefile: split off SPATCH_BATCH_SIZE comment from "cocci" heading Ævar Arnfjörð Bjarmason
2022-08-31 20:57 ` [PATCH v2 5/9] cocci: split off include-less "tests" from SPATCH_FLAGS Ævar Arnfjörð Bjarmason
2022-08-31 20:57 ` [PATCH v2 6/9] cocci: split off "--all-includes" " Ævar Arnfjörð Bjarmason
2022-08-31 20:57 ` [PATCH v2 7/9] cocci: make "coccicheck" rule incremental Ævar Arnfjörð Bjarmason
2022-09-01 16:38 ` SZEDER Gábor
2022-09-01 18:04 ` Ævar Arnfjörð Bjarmason
2022-08-31 20:57 ` [PATCH v2 8/9] cocci: optimistically use COMPUTE_HEADER_DEPENDENCIES Ævar Arnfjörð Bjarmason
2022-08-31 20:57 ` [PATCH v2 9/9] spatchcache: add a ccache-alike for "spatch" Ævar Arnfjörð Bjarmason
2022-10-14 15:31 ` [PATCH v3 00/11] cocci: make "incremental" possible + a ccache-like tool Ævar Arnfjörð Bjarmason
2022-10-14 15:31 ` [PATCH v3 01/11] Makefile + shared.mak: rename and indent $(QUIET_SPATCH_T) Ævar Arnfjörð Bjarmason
2022-10-14 15:31 ` [PATCH v3 02/11] cocci rules: remove unused "F" metavariable from pending rule Ævar Arnfjörð Bjarmason
2022-10-14 15:31 ` [PATCH v3 03/11] Makefile: add ability to TAB-complete cocci *.patch rules Ævar Arnfjörð Bjarmason
2022-10-14 15:31 ` [PATCH v3 04/11] Makefile: have "coccicheck" re-run if flags change Ævar Arnfjörð Bjarmason
2022-10-14 15:31 ` [PATCH v3 05/11] Makefile: split off SPATCH_BATCH_SIZE comment from "cocci" heading Ævar Arnfjörð Bjarmason
2022-10-14 20:39 ` Taylor Blau
2022-10-14 15:31 ` [PATCH v3 06/11] cocci: split off include-less "tests" from SPATCH_FLAGS Ævar Arnfjörð Bjarmason
2022-10-14 15:31 ` [PATCH v3 07/11] cocci: split off "--all-includes" " Ævar Arnfjörð Bjarmason
2022-10-14 15:31 ` [PATCH v3 08/11] cocci: make "coccicheck" rule incremental Ævar Arnfjörð Bjarmason
2022-10-14 15:31 ` [PATCH v3 09/11] cocci: optimistically use COMPUTE_HEADER_DEPENDENCIES Ævar Arnfjörð Bjarmason
2022-10-14 15:31 ` [PATCH v3 10/11] cocci: run against a generated ALL.cocci Ævar Arnfjörð Bjarmason
2022-10-14 15:31 ` [PATCH v3 11/11] spatchcache: add a ccache-alike for "spatch" Ævar Arnfjörð Bjarmason
2022-10-17 17:50 ` [PATCH v3 00/11] cocci: make "incremental" possible + a ccache-like tool Jeff King
2022-10-17 18:36 ` Ævar Arnfjörð Bjarmason
2022-10-17 19:08 ` Junio C Hamano
2022-10-17 19:18 ` Jeff King
2022-10-26 14:20 ` [PATCH v4 00/12] " Ævar Arnfjörð Bjarmason
2022-10-26 14:20 ` [PATCH v4 01/12] Makefile + shared.mak: rename and indent $(QUIET_SPATCH_T) Ævar Arnfjörð Bjarmason
2022-10-26 14:20 ` [PATCH v4 02/12] cocci rules: remove unused "F" metavariable from pending rule Ævar Arnfjörð Bjarmason
2022-10-26 14:20 ` [PATCH v4 03/12] Makefile: add ability to TAB-complete cocci *.patch rules Ævar Arnfjörð Bjarmason
2022-10-26 14:20 ` [PATCH v4 04/12] Makefile: have "coccicheck" re-run if flags change Ævar Arnfjörð Bjarmason
2022-10-26 14:20 ` [PATCH v4 05/12] Makefile: split off SPATCH_BATCH_SIZE comment from "cocci" heading Ævar Arnfjörð Bjarmason
2022-10-26 14:20 ` [PATCH v4 06/12] cocci: split off include-less "tests" from SPATCH_FLAGS Ævar Arnfjörð Bjarmason
2022-10-26 14:20 ` [PATCH v4 07/12] cocci: split off "--all-includes" " Ævar Arnfjörð Bjarmason
2022-10-26 14:20 ` [PATCH v4 08/12] cocci: make "coccicheck" rule incremental Ævar Arnfjörð Bjarmason
2022-10-26 14:20 ` [PATCH v4 09/12] cocci: optimistically use COMPUTE_HEADER_DEPENDENCIES Ævar Arnfjörð Bjarmason
2022-10-26 14:20 ` [PATCH v4 10/12] cocci rules: remove <id>'s from rules that don't need them Ævar Arnfjörð Bjarmason
2022-10-26 14:20 ` [PATCH v4 11/12] cocci: run against a generated ALL.cocci Ævar Arnfjörð Bjarmason
2022-10-28 12:58 ` SZEDER Gábor
2022-10-26 14:20 ` [PATCH v4 12/12] spatchcache: add a ccache-alike for "spatch" Ævar Arnfjörð Bjarmason
2022-11-01 22:35 ` [PATCH v5 00/13] cocci: make "incremental" possible + a ccache-like tool Ævar Arnfjörð Bjarmason
2022-11-01 22:35 ` [PATCH v5 01/13] Makefile + shared.mak: rename and indent $(QUIET_SPATCH_T) Ævar Arnfjörð Bjarmason
2022-11-01 22:35 ` [PATCH v5 02/13] cocci rules: remove unused "F" metavariable from pending rule Ævar Arnfjörð Bjarmason
2022-11-01 22:35 ` [PATCH v5 03/13] Makefile: add ability to TAB-complete cocci *.patch rules Ævar Arnfjörð Bjarmason
2022-11-01 22:35 ` [PATCH v5 04/13] Makefile: have "coccicheck" re-run if flags change Ævar Arnfjörð Bjarmason
2022-11-01 22:35 ` [PATCH v5 05/13] Makefile: split off SPATCH_BATCH_SIZE comment from "cocci" heading Ævar Arnfjörð Bjarmason
2022-11-01 22:35 ` [PATCH v5 06/13] cocci: split off include-less "tests" from SPATCH_FLAGS Ævar Arnfjörð Bjarmason
2022-11-01 22:35 ` [PATCH v5 07/13] cocci: split off "--all-includes" " Ævar Arnfjörð Bjarmason
2022-11-01 22:35 ` [PATCH v5 08/13] cocci: make "coccicheck" rule incremental Ævar Arnfjörð Bjarmason
2022-11-09 14:57 ` SZEDER Gábor
2022-11-01 22:35 ` [PATCH v5 09/13] cocci: optimistically use COMPUTE_HEADER_DEPENDENCIES Ævar Arnfjörð Bjarmason
2022-11-01 22:35 ` [PATCH v5 10/13] Makefile: copy contrib/coccinelle/*.cocci to build/ Ævar Arnfjörð Bjarmason
2022-11-09 15:05 ` SZEDER Gábor
2022-11-09 15:42 ` Ævar Arnfjörð Bjarmason
2022-11-10 16:14 ` [PATCH] Makefile: don't create a ".build/.build/" for cocci, fix output Ævar Arnfjörð Bjarmason
2022-11-11 22:22 ` Taylor Blau
2022-11-01 22:35 ` [PATCH v5 11/13] cocci rules: remove <id>'s from rules that don't need them Ævar Arnfjörð Bjarmason
2022-11-01 22:35 ` [PATCH v5 12/13] cocci: run against a generated ALL.cocci Ævar Arnfjörð Bjarmason
2022-11-01 22:35 ` [PATCH v5 13/13] spatchcache: add a ccache-alike for "spatch" Ævar Arnfjörð Bjarmason
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