From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Jeff King <peff@peff.net>
Cc: git@vger.kernel.org, "Junio C Hamano" <gitster@pobox.com>,
"René Scharfe" <l.s.r@web.de>,
"SZEDER Gábor" <szeder.dev@gmail.com>, "Eric Wong" <e@80x24.org>,
"Denton Liu" <liu.denton@gmail.com>
Subject: Re: [PATCH v2 2/4] Makefile/coccicheck: speed up and fix bug with duplicate hunks
Date: Sat, 06 Mar 2021 20:29:05 +0100 [thread overview]
Message-ID: <87lfb0jd32.fsf@evledraar.gmail.com> (raw)
In-Reply-To: <YENdUMLTM+cerfqJ@coredump.intra.peff.net>
On Sat, Mar 06 2021, Jeff King wrote:
> On Fri, Mar 05, 2021 at 06:07:22PM +0100, Ævar Arnfjörð Bjarmason wrote:
>
>> Using --no-includes also fixes a subtle bug introduced in
>> 960154b9c17 (coccicheck: optionally batch spatch invocations,
>> 2019-05-06) with duplicate hunks being written to the
>> generated *.patch files.
>>
>> This is because that change altered a file-at-a-time for-loop to an
>> invocation of "xargs -n X". This would not matter for most other
>> programs, but it matters for spatch.
>>
>> This is because each spatch invocation will maintain shared lock files
>> in /tmp, check if files being parsed were changed etc. I haven't dug
>> into why exactly, but it's easy to reproduce the issue[2]. The issue
>> goes away entirely if we just use --no-includes, which as noted above
>> would have made sense even without that issue.
>
> This part still doesn't make any sense to me. If we are running with
> SPATCH_BATCH_SIZE=1, which is the default, then "xargs -n" is still
> going to run it in file-at-a-time mode. From spatch's perspective,
> there's no difference between a for-loop and "xargs -n 1" (unless it
> somehow cares about stdin, but it shouldn't).
>
> Using strace, I do see it creating files in /tmp, but they are all named
> after the process id, and cleaned up before exit. So I don't see how
> they could interfere with each other (certainly not in a sequential run,
> but even if you were to use "xargs -P" to get parallel runs, they seem
> distinct).
>
> If we increase the batch size, I'd expect _fewer_ duplicates. Because in
> file-at-a-time mode with --all-includes, wouldn't every file that
> mentions an include possibly end up emitting a patch for it?
>
> The results you show here (which do replicate for me) imply something
> much weirder is going on:
>
>> with xargs -n 1:
>> 1 +++ b/convert.c
>> 1 +++ b/strbuf.c
>> with xargs -n 2:
>> 1 +++ b/convert.c
>> 1 +++ b/strbuf.c
>> with xargs -n 4:
>> 1 +++ b/convert.c
>> 1 +++ b/strbuf.c
>
> These results are wrong! They are not finding the entry in strbuf.h that
> should be changed.
>
>> with xargs -n 16:
>> 1 +++ b/convert.c
>> 1 +++ b/strbuf.c
>> 2 +++ b/strbuf.h
>> with xargs -n 64:
>> 1 +++ b/convert.c
>> 1 +++ b/strbuf.c
>> 2 +++ b/strbuf.h
>> with xargs -n 128:
>> 1 +++ b/convert.c
>> 1 +++ b/strbuf.c
>> 2 +++ b/strbuf.h
>
> These ones are also wrong. Now we find the strbuf.h mention, but we are
> finding it twice.
>
>> with xargs -n 512:
>> 1 +++ b/convert.c
>> 1 +++ b/strbuf.c
>> 1 +++ b/strbuf.h
>
> And this one, which is given all of the paths in one invocation gets it
> right. I'd expect that over the "128" version, which is running two
> independent spatch invocations. But the fact that "64" and "16" produce
> exactly two duplicates makes little sense. And even less that 1, 2, and
> 4 don't find the header change at all.
Yes, I don't know what's going on with spatch. Just the observed results
of duplication before/after youc commit.
> Running the same test with a for loop produces the same (wrong) results
> as "-n 1", as expected:
>
> $ for i in *.c; do
> spatch --sp-file test.cocci --all-includes --patch . $i 2>/dev/null
> done | grep -F +++ | sort | uniq -c
> 1 +++ b/convert.c
> 1 +++ b/strbuf.c
>
> So in short I have no idea what spatch is doing. But I remain
> unconvinced that there is anything wrong with the batch-size patch.
Right, but that's an unrelated "didn't change this thing it should have"
bug (which we had before), not the duplicate hunk bug.
> Running it like your patch will, feeding the header directly along with
> --no-includes, does find the correct result:
>
> $ for i in *.c *.h; do
> spatch --sp-file test.cocci --no-includes --patch . $i 2>/dev/null
> done | grep -F +++ | sort | uniq -c
> 1 +++ b/convert.c
> 1 +++ b/strbuf.c
> 1 +++ b/strbuf.h
>
> though I am still concerned by René's example which is missing more
> results.
*nod*. I just sent a patch on top to fix that, although it undoes most
of the speedup in this series.
next prev parent reply other threads:[~2021-03-06 19:30 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-12 23:48 [RFC PATCH] *.h: remove extern from function declarations Denton Liu
2019-04-13 1:24 ` Jeff King
2019-04-13 5:45 ` Junio C Hamano
2019-04-15 18:24 ` [PATCH v2 0/3] " Denton Liu
2019-04-15 18:24 ` [PATCH v2 1/3] *.[ch]: remove extern from function declarations using spatch Denton Liu
2019-04-15 19:19 ` Thomas Gummerer
2019-04-15 18:24 ` [PATCH v2 2/3] *.[ch]: remove extern from function declarations using sed Denton Liu
2019-04-15 18:24 ` [PATCH v2 3/3] cocci: prevent extern function declarations Denton Liu
2019-04-17 7:58 ` [PATCH v3 0/4] remove extern from " Denton Liu
2019-04-17 7:58 ` [PATCH v3 1/4] *.[ch]: remove extern from function declarations using spatch Denton Liu
2019-04-17 7:58 ` [PATCH v3 2/4] *.[ch]: remove extern from function declarations using sed Denton Liu
2019-04-17 7:58 ` [PATCH v3 3/4] *.[ch]: manually align parameter lists Denton Liu
2019-04-17 7:58 ` [PATCH v3 4/4] cocci: prevent extern function declarations Denton Liu
2019-04-22 5:44 ` [PATCH] cache.h: fix mismerge of 'dl/no-extern-in-func-decl' Denton Liu
2019-04-22 6:30 ` Junio C Hamano
2019-04-22 11:19 ` Junio C Hamano
2019-04-22 21:49 ` [PATCH v3 0/4] remove extern from function declarations Jeff King
2019-04-25 12:07 ` SZEDER Gábor
2019-04-25 18:05 ` Denton Liu
2019-04-30 23:21 ` Johannes Schindelin
2019-05-01 10:01 ` Denton Liu
2019-05-01 18:56 ` Jeff King
2019-05-02 0:04 ` SZEDER Gábor
2019-05-03 9:32 ` Johannes Schindelin
2019-05-03 14:42 ` SZEDER Gábor
2019-05-03 14:58 ` SZEDER Gábor
2019-05-03 17:45 ` Jeff King
2019-05-03 18:44 ` SZEDER Gábor
2019-05-05 5:28 ` Junio C Hamano
2019-05-05 18:09 ` Jacob Keller
2019-05-05 18:08 ` Jacob Keller
2019-05-06 5:11 ` [PATCH] coccicheck: optionally process every source file at once Jeff King
2019-05-06 9:34 ` Duy Nguyen
2019-05-06 23:43 ` [PATCH] coccicheck: optionally batch spatch invocations Jeff King
2019-05-07 1:41 ` Jacob Keller
2019-05-07 2:04 ` Jeff King
2019-05-07 2:42 ` Junio C Hamano
2019-05-07 2:55 ` Jeff King
2019-05-07 3:04 ` Jacob Keller
2019-05-07 4:52 ` Junio C Hamano
2019-05-08 7:07 ` Jeff King
2019-05-08 12:36 ` Denton Liu
2019-05-08 22:39 ` Jeff King
2019-05-07 10:20 ` Duy Nguyen
2019-05-07 11:19 ` SZEDER Gábor
2021-03-02 20:51 ` [PATCH] Makefile: fix bugs in coccicheck and speed it up Ævar Arnfjörð Bjarmason
2021-03-03 9:43 ` Denton Liu
2021-03-03 11:45 ` Ævar Arnfjörð Bjarmason
2021-03-04 23:18 ` Junio C Hamano
2021-03-05 11:17 ` Ævar Arnfjörð Bjarmason
2021-03-05 10:24 ` Jeff King
2021-03-05 17:20 ` Ævar Arnfjörð Bjarmason
2021-03-06 10:59 ` Jeff King
2021-03-05 17:07 ` [PATCH v2 0/4] Makefile/coccicheck: fix bugs " Ævar Arnfjörð Bjarmason
2021-03-05 19:10 ` René Scharfe.
[not found] ` <xmqqim659u57.fsf@gitster.c.googlers.com>
2021-03-06 11:26 ` René Scharfe.
2021-03-06 12:43 ` René Scharfe.
[not found] ` <xmqqft16914r.fsf@gitster.c.googlers.com>
2021-03-13 16:10 ` René Scharfe.
2021-03-06 17:27 ` Ævar Arnfjörð Bjarmason
2021-03-06 17:41 ` René Scharfe.
2021-03-06 17:52 ` Ævar Arnfjörð Bjarmason
2021-03-06 19:08 ` René Scharfe.
2021-03-05 17:07 ` [PATCH v2 1/4] Makefile/coccicheck: add comment heading for all SPATCH flags Ævar Arnfjörð Bjarmason
2021-03-05 17:07 ` [PATCH v2 2/4] Makefile/coccicheck: speed up and fix bug with duplicate hunks Ævar Arnfjörð Bjarmason
2021-03-06 10:45 ` Jeff King
2021-03-06 19:29 ` Ævar Arnfjörð Bjarmason [this message]
2021-03-05 17:07 ` [PATCH v2 3/4] Makefile/coccicheck: allow for setting xargs concurrency Ævar Arnfjörð Bjarmason
2021-03-06 10:51 ` Jeff King
2021-03-05 17:07 ` [PATCH v2 4/4] Makefile/coccicheck: set SPATCH_BATCH_SIZE to 8 Ævar Arnfjörð Bjarmason
2021-03-06 19:25 ` [PATCH v2 5/4] Makefile/coccicheck: use --include-headers-for-types Ævar Arnfjörð Bjarmason
2021-03-18 20:49 ` SZEDER Gábor
2021-03-19 10:32 ` Ævar Arnfjörð Bjarmason
2021-03-22 12:11 ` [PATCH v4 0/4] Makefile/coccicheck: fix bugs and speed it up Ævar Arnfjörð Bjarmason
2021-03-22 12:11 ` [PATCH v4 1/4] Makefile/coccicheck: add comment heading for all SPATCH flags Ævar Arnfjörð Bjarmason
2021-03-22 18:04 ` René Scharfe.
2021-03-22 12:11 ` [PATCH v4 2/4] Makefile/coccicheck: speed up and fix bug with duplicate hunks Ævar Arnfjörð Bjarmason
2021-03-22 18:05 ` René Scharfe.
2021-03-24 19:19 ` Jeff King
2021-03-22 19:09 ` Junio C Hamano
2021-03-22 12:11 ` [PATCH v4 3/4] Makefile/coccicheck: allow for setting xargs concurrency Ævar Arnfjörð Bjarmason
2021-03-24 19:26 ` Jeff King
2021-03-25 2:29 ` Ævar Arnfjörð Bjarmason
2021-03-26 4:11 ` Jeff King
2021-03-22 12:11 ` [PATCH v4 4/4] Makefile/coccicheck: set SPATCH_BATCH_SIZE to 8 Ævar Arnfjörð Bjarmason
2021-03-22 18:05 ` René Scharfe.
2021-03-24 19:27 ` Jeff King
2021-03-27 17:43 ` [PATCH v4 0/4] Makefile/coccicheck: fix bugs and speed it up Junio C Hamano
2021-03-27 19:46 ` Ævar Arnfjörð Bjarmason
2019-05-03 9:40 ` [PATCH v3 0/4] remove extern from function declarations Denton Liu
2019-04-23 23:40 ` [PATCH v4 " Denton Liu
2019-04-23 23:40 ` [PATCH v4 1/4] *.[ch]: remove extern from function declarations using spatch Denton Liu
2019-04-23 23:40 ` [PATCH v4 2/4] *.[ch]: remove extern from function declarations using sed Denton Liu
2019-04-24 4:56 ` Junio C Hamano
2019-04-25 19:00 ` Denton Liu
2019-04-23 23:40 ` [PATCH v4 3/4] *.[ch]: manually align parameter lists Denton Liu
2019-04-23 23:40 ` [PATCH v4 4/4] cocci: prevent extern function declarations Denton Liu
2019-04-29 8:28 ` [PATCH v5 0/3] *** SUBJECT HERE *** Denton Liu
2019-04-29 8:28 ` [PATCH v5 1/3] *.[ch]: remove extern from function declarations using spatch Denton Liu
2019-04-29 8:28 ` [PATCH v5 2/3] *.[ch]: remove extern from function declarations using sed Denton Liu
2019-04-29 8:28 ` [PATCH v5 3/3] *.[ch]: manually align parameter lists Denton Liu
2019-04-29 8:30 ` [PATCH v5 0/3] *** SUBJECT HERE *** Denton Liu
2019-05-06 11:03 ` Ævar Arnfjörð Bjarmason
2019-05-06 15:34 ` Denton Liu
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