public inbox for glibc-cvs@sourceware.org help / color / mirror / Atom feed
From: Adhemerval Zanella <azanella@sourceware.org> To: glibc-cvs@sourceware.org Subject: [glibc] stdlib: Tuned down tst-arc4random-thread internal parameters Date: Fri, 29 Jul 2022 12:24:13 +0000 (GMT) [thread overview] Message-ID: <20220729122413.2D9EF3858429@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=35363b53cef00c3b9886b2c1f45612869f304960 commit 35363b53cef00c3b9886b2c1f45612869f304960 Author: Adhemerval Zanella <adhemerval.zanella@linaro.org> Date: Wed Jul 27 08:59:15 2022 -0300 stdlib: Tuned down tst-arc4random-thread internal parameters With new arc4random implementation, the internal parameters might require a lot of runtime and/or trigger some contention on older kernels (which might trigger spurious timeout failures). Also, since we are now testing getrandom entropy instead of an userspace RNG, there is no much need to extensive testing. With this change the tst-arc4random-thread goes from about 1m to 5s on a Ryzen 9 with 5.15.0-41-generic. Checked on x86_64-linux-gnu. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com> Diff: --- stdlib/tst-arc4random-thread.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/stdlib/tst-arc4random-thread.c b/stdlib/tst-arc4random-thread.c index 3373d4d446..daba828fad 100644 --- a/stdlib/tst-arc4random-thread.c +++ b/stdlib/tst-arc4random-thread.c @@ -17,23 +17,23 @@ <https://www.gnu.org/licenses/>. */ #include <array_length.h> +#include <sched.h> #include <stdio.h> -#include <string.h> #include <stdlib.h> +#include <string.h> #include <support/check.h> #include <support/namespace.h> #include <support/support.h> #include <support/xthread.h> /* Number of arc4random_buf calls per thread. */ -enum { count_per_thread = 5000 }; +enum { count_per_thread = 2048 }; /* Number of threads computing randomness. */ -enum { inner_threads = 5 }; +enum { inner_threads = 4 }; -/* Number of threads launching other threads. Chosen as to not to - overload the system. */ -enum { outer_threads = 7 }; +/* Number of threads launching other threads. */ +static int outer_threads = 1; /* Number of launching rounds performed by the outer threads. */ enum { outer_rounds = 10 }; @@ -331,6 +331,18 @@ do_test_func (const char *fname, void (*func)(unsigned char *, size_t)) static int do_test (void) { + /* Do not run more threads than the maximum of schedulable CPUs. */ + cpu_set_t cpuset; + if (sched_getaffinity (0, sizeof cpuset, &cpuset) == 0) + { + unsigned int ncpus = CPU_COUNT (&cpuset); + /* Limit the number to not overload the system. */ + outer_threads = (ncpus / 2) / inner_threads ?: 1; + } + + printf ("info: outer_threads=%d inner_threads=%d\n", outer_threads, + inner_threads); + do_test_func ("arc4random", generate_arc4random); do_test_func ("arc4random_buf", generate_arc4random_buf); do_test_func ("arc4random_uniform", generate_arc4random_uniform);
reply other threads:[~2022-07-29 12:24 UTC|newest] Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20220729122413.2D9EF3858429@sourceware.org \ --to=azanella@sourceware.org \ --cc=glibc-cvs@sourceware.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).