From: Jeff King <peff@peff.net>
To: "René Scharfe" <l.s.r@web.de>
Cc: "Junio C Hamano" <gitster@pobox.com>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"Git List" <git@vger.kernel.org>
Subject: Re: [PATCH 10/9 v2] test-mergesort: use repeatable random numbers
Date: Fri, 8 Oct 2021 00:17:22 -0400 [thread overview]
Message-ID: <YV/GUg3yXDfuS3BA@coredump.intra.peff.net> (raw)
In-Reply-To: <b73452fa-f5b0-0ab4-25e8-7494637c49f5@web.de>
On Fri, Oct 08, 2021 at 06:04:42AM +0200, René Scharfe wrote:
> Use MINSTD to generate pseudo-random numbers consistently instead of
> using rand(3), whose output can vary from system to system, and reset
> its seed before filling in the test values. This gives repeatable
> results across versions and systems, which simplifies sharing and
> comparing of results between developers.
Nice. As a bonus, I noticed that Coverity complains about the use of
rand() as a security red-flag (even though of course we don't care about
its quality here). This should get rid of it by hiding the same thing in
a custom implementation. ;)
We have a similar LCG in t/helper/test-genrandom.c, but I don't think
there's any reason this needs to be factored into a shared one. And in
particular, I'd be loathe to change the genrandom one, as it may create
small bugs in the test suite (cases where we rely on hashes of the data
having particular attributes).
-Peff
next prev parent reply other threads:[~2021-10-08 4:17 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-01 9:07 [PATCH 0/9] mergesort: improve tests and performance René Scharfe
2021-10-01 9:10 ` [PATCH 1/9] test-mergesort: use strbuf_getline() René Scharfe
2021-10-02 9:08 ` Ævar Arnfjörð Bjarmason
2021-10-02 16:56 ` René Scharfe
2021-10-01 9:11 ` [PATCH 2/9] test-mergesort: add sort subcommand René Scharfe
2021-10-01 20:26 ` Junio C Hamano
2021-10-01 9:12 ` [PATCH 3/9] test-mergesort: add test subcommand René Scharfe
2021-10-01 20:26 ` Junio C Hamano
2021-10-02 8:35 ` Ævar Arnfjörð Bjarmason
2021-10-03 10:15 ` René Scharfe
2021-10-03 17:33 ` Junio C Hamano
2021-10-07 20:00 ` René Scharfe
2021-10-08 4:04 ` [PATCH 10/9 v2] test-mergesort: use repeatable random numbers René Scharfe
2021-10-08 4:17 ` Jeff King [this message]
2021-10-08 7:23 ` Ævar Arnfjörð Bjarmason
2021-10-08 17:30 ` René Scharfe
2021-10-08 19:00 ` Ævar Arnfjörð Bjarmason
2021-10-03 10:15 ` [PATCH 3/9] test-mergesort: add test subcommand René Scharfe
2021-10-01 9:14 ` [PATCH 4/9] test-mergesort: add generate subcommand René Scharfe
2021-10-01 9:16 ` [PATCH 5/9] test-mergesort: add unriffle mode René Scharfe
2021-10-01 9:17 ` [PATCH 6/9] test-mergesort: add unriffle_skewed mode René Scharfe
2021-10-01 9:19 ` [PATCH 7/9] p0071: measure sorting of already sorted and reversed files René Scharfe
2021-10-01 9:19 ` [PATCH 8/9] p0071: test performance of llist_mergesort() René Scharfe
2021-10-01 9:22 ` [PATCH 9/9] mergesort: use ranks stack René Scharfe
2022-01-17 17:43 ` Ævar Arnfjörð Bjarmason
2022-01-17 18:22 ` René Scharfe
2022-01-18 5:07 ` René Scharfe
2022-01-18 10:40 ` Ævar Arnfjörð Bjarmason
2022-01-18 12:27 ` René Scharfe
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