Messages in this thread | | | Date | Mon, 30 Jan 2023 17:49:30 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH v4] posix-timers: Prefer delivery of signals to the current thread |
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On 01/30, Dmitry Vyukov wrote: > > On Sat, 28 Jan 2023 at 20:56, Oleg Nesterov <oleg@redhat.com> wrote: > > > > Dmitry, > > > > I agree with what you said, just one note... > > > > On 01/27, Dmitry Vyukov wrote: > > > > > > After this change the test passes quickly (within a second for me). > > > > yet perhaps it makes sense to slightly change it? It does > > > > +static void *distribution_thr(void *arg) { > > + while (__atomic_load_n(&remain, __ATOMIC_RELAXED)); > > + return NULL; > > +} > > > > so distribution_thr() eats CPU even after this thread gets a signal and thus > > (in theory) it can "steal" cpu_timer_fire() from other threads unpredictably > > long ? How about > > > > - while (__atomic_load_n(&remain, __ATOMIC_RELAXED)); > > + while (__atomic_load_n(&got_signal, __ATOMIC_RELAXED)); > > ? > > But why? > IIUC this makes the test even "weaker". As Thomas notes it's already > somewhat "weak". And this would make it even "weaker".
Not sure I understand why can this change make the test more weak...
IIUC, _in theory_ the test-case can "hang" forever, since all threads are running nothing guarentees that every thread will have a chance to call cpu_timer_fire() and get a signal.
With this change this is not possible, and the test-case will still verify that all threads must get a signal.
Nevermind,
> So if it passes > in the current version, I would keep it as is.
OK, I won't insist, please forget.
Oleg.
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