RE: [RFC 0/2] qemu-sem-posix: use monotonic clock instead

[longpeng2--- via <qemu-devel@nongnu.org>]

> -----Original Message-----
> From: Paolo Bonzini [mailto:paolo.bonzini@gmail.com] On Behalf Of Paolo Bonzini
> Sent: Monday, February 21, 2022 7:31 PM
> To: Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
> <longpeng2@huawei.com>; berrange@redhat.com; mst@redhat.com
> Cc: qemu-devel@nongnu.org; Gonglei (Arei) <arei.gonglei@huawei.com>
> Subject: Re: [RFC 0/2] qemu-sem-posix: use monotonic clock instead
> 
> On 2/21/22 10:56, Longpeng(Mike) via wrote:
> > The qemu_sem_timedwait() uses system time as default, it would be affected
> by
> > changes to the system time. In the real scenario, the time that goes faster
> or
> > slower is a common case and the NTP service could help us to sync time
> > periodically.
> >
> > This patchset uses monotonic clock instead of the realtime clock, this could
> > make sure we would not be affected by the system time anymore.
> 
> This looks good, I don't think there are cases where a more optimized
> semaphore is necessary (if there were, we could introduce a futex
> fallback on Linux).
> 
> However, pthread_condattr_t need not be in the struct.  The attributes
> can be allocated on the stack, because they do not have to remain alive
> after pthread_cond_init.
> 

OK, will do in the next version, thanks!

> Thanks,
> 
> Paolo
> 
> > Longpeng (Mike) (2):
> >    sem-posix: remove the posix semaphore support
> >    sem-posix: use monotonic clock instead
> >
> >   include/qemu/thread-posix.h |  5 +--
> >   meson.build                 | 12 ++++++-
> >   util/qemu-thread-posix.c    | 82
> +++++++++++++++------------------------------
> >   3 files changed, 39 insertions(+), 60 deletions(-)
> >