From: Samuel Thibault <samuel.thibault@ens-lyon.org>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>,
GNU C Library <libc-alpha@sourceware.org>
Subject: Re: [PATCH] tst: Provide test for select
Date: Wed, 24 Mar 2021 22:35:43 +0100 [thread overview]
Message-ID: <20210324213543.4ixrs66lloe7x6lx@begin> (raw)
In-Reply-To: <CAMe9rOrPegW9nLWSs3uA6O9fJvo8_guz5SUuzzhwrLTuQk_UyQ@mail.gmail.com>
H.J. Lu via Libc-alpha, le mer. 24 mars 2021 14:21:54 -0700, a ecrit:
> On Wed, Mar 24, 2021 at 2:14 PM Adhemerval Zanella
> <adhemerval.zanella@linaro.org> wrote:
> >
> >
> >
> > On 24/03/2021 17:13, H.J. Lu wrote:
> > > On Wed, Mar 24, 2021 at 12:47 PM Adhemerval Zanella
> > > <adhemerval.zanella@linaro.org> wrote:
> > >>
> > >>
> > >>
> > >> On 24/03/2021 16:17, H.J. Lu wrote:
> > >>> On Mon, Mar 22, 2021 at 4:33 AM Lukasz Majewski <lukma@denx.de> wrote:
> > >>>>
> > >>>> Dear Community,
> > >>>>
> > >>>>> This change adds new test to assess select()'s timeout related
> > >>>>> functionality (the rdfs set provides valid fd - stderr - but during
> > >>>>> normal program operation there is no data to be read, so one just
> > >>>>> waits for timeout).
> > >>>>>
> > >>>>> To be more specific - two use cases are checked:
> > >>>>> - if select() times out immediately when passed struct timeval has
> > >>>>> zero values of tv_usec and tv_sec.
> > >>>>> - if select() times out after timeout specified in passed argument
> > >>>>
> > >>>> Do you have any comments regarding this patch?
> > >>>>
> > >>>
> > >>> This test failed on machines with more than 40 cores:
> > >>>
> > >>> tst-select.c:54: 1616610088.851713938s not after 1616610089.851712804s
> > >>> (difference 0.999998866s)
> > >>> error: 1 test failures
> > >>>
> > >>> I was doing 3 "makec -j28 check" in parallel.
> > >>
> > >> I think the nanosecond precision of time accounting is triggering the
> > >> failure, since select only support timeval (the error indicates that
> > >> the nanosecond precision is what is triggering it).
> > >>
> > >> Maybe if we ignore the nanosecond precision:
> > >>
> > >> diff --git a/misc/tst-select.c b/misc/tst-select.c
> > >> index 7c310256c5..4b1791ac8a 100644
> > >> --- a/misc/tst-select.c
> > >> +++ b/misc/tst-select.c
> > >> @@ -45,6 +45,8 @@ test_select_timeout (bool zero_tmo)
> > >> to.tv_sec = timeout;
> > >> ts = xclock_now (CLOCK_REALTIME);
> > >> ts = timespec_add (ts, (struct timespec) { timeout, 0 });
> > >> + /* Ignore nanosecond precision since select only support microsecond. */
> > >> + ts.tv_nsec = (ts.tv_nsec * 1000) / 1000;
> > >
> > > How does it work? It looks like a NOP to me.
> >
> > The idea is to clear the nanosecond precision from the xclock_now call.
It should rather be
ts.tv_nsec = (ts.tv_nsec / 1000) * 1000;
shouldn't it?
Samuel
next prev parent reply other threads:[~2021-03-24 21:35 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-14 16:46 Lukasz Majewski
2021-03-14 19:17 ` DJ Delorie
2021-03-15 9:50 ` Lukasz Majewski
2021-03-15 17:11 ` DJ Delorie
2021-03-22 11:32 ` Lukasz Majewski
2021-03-24 19:17 ` H.J. Lu
2021-03-24 19:47 ` Adhemerval Zanella
2021-03-24 20:13 ` H.J. Lu
2021-03-24 21:14 ` Adhemerval Zanella
2021-03-24 21:21 ` H.J. Lu
2021-03-24 21:24 ` Adhemerval Zanella
2021-03-24 21:35 ` Samuel Thibault [this message]
2021-03-24 21:43 ` Adhemerval Zanella
2021-03-24 22:30 ` H.J. Lu
2021-03-25 11:35 ` Adhemerval Zanella
2021-03-25 12:20 ` Andreas Schwab
2021-03-25 12:48 ` Adhemerval Zanella
2021-03-25 13:22 ` H.J. Lu
2021-03-25 13:31 ` Adhemerval Zanella
2021-03-22 19:23 ` Adhemerval Zanella
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=20210324213543.4ixrs66lloe7x6lx@begin \
--to=samuel.thibault@ens-lyon.org \
--cc=adhemerval.zanella@linaro.org \
--cc=hjl.tools@gmail.com \
--cc=libc-alpha@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: link
Be 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).