Re: [PATCH] util: qemu_get_thread_id for OpenBSD

[Peter Maydell]

On Wed, 15 Jul 2020 at 08:41, Brad Smith <brad@comstyle.com> wrote:
>
> On 7/15/2020 12:54 AM, Thomas Huth wrote:
> > On 14/07/2020 23.26, David CARLIER wrote:
> >>  From 9c7f54c67d40fae0174ba795fbaad829cd59c264 Mon Sep 17 00:00:00 2001
> >> From: David Carlier <devnexen@gmail.com>
> >> Date: Tue, 14 Jul 2020 23:23:55 +0100
> >> Subject: [PATCH] util: qemu_get_thread_id implementation for OpenBSD.
> >>
> >> ussage of getthrid syscall.
> >>
> >> Signed-off-by: David Carlier <devnexen@gmail.com>
> >> ---
> >>   util/oslib-posix.c | 2 ++
> >>   1 file changed, 2 insertions(+)
> >>
> >> diff --git a/util/oslib-posix.c b/util/oslib-posix.c
> >> index 72907d4d7f..b4f7de83c8 100644
> >> --- a/util/oslib-posix.c
> >> +++ b/util/oslib-posix.c
> >> @@ -100,6 +100,8 @@ int qemu_get_thread_id(void)
> >>       return (int)tid;
> >>   #elif defined(__NetBSD__)
> >>       return _lwp_self();
> >> +#elif defined(__OpenBSD__)
> >> +    return getthrid();
> >>   #else
> >>       return getpid();
> >>   #endif
> >>
> >   Brad,
> >
> > since you're listed as OpenBSD maintainer, could you please review above
> > patch?
>
> Thank you David and Thomas.
>
> Reviewed-by: Brad Smith <brad@comstyle.com>

Thanks for the review. Since this is a one-liner I'll take it into
the tree via target-arm.next just for convenience.

Side note: the only things we use this value for are:
 (1) it appears in the output of the QMP monitor's query-cpus and
query-iothreads commands, so that a management layer app can
use whatever the host OS provides for setting host CPU
affinity to tie a particular guest vCPU thread to a host CPU.
 (2) the log tracing backend uses it in the output just as a
way to allow tracing from different threads to be distinguished

We should really write a doc comment explaining that. Maybe
I'll put a patch together.

thanks
-- PMM