FreeBSD 11.x thread creation time is 9000+ microseconds on Intel Xeon Gold series CPU

[Steevan Rodrigues]

I tried FreeBSD 12 Beta 3 version  on this server with Xeon Gold 5115 CPU.
All these problems have disappeared.  Thread creation time has improved
greatly .
It is now  below 100 usec ( in FreeBSD 11.x  9000+ usec)

Also I had another issue  with FreeBSD 11.x which related to contigmalloc
and contigfree .
Actually contigfree was taking too much time on FreeBSD 11.x  on this same
server with Xeon Gold 5115 CPU.

In FreeBSD 12 Beta3  also contigfree takes much more time compared to
contigmalloc.
However  when I compare the  values to FreeBSD 11.x number I can see huge
improvement in FreeBSD 12 Beta 3   .
Because of this contigfree issue my driver unload  used to take 5 to 20
minutes  in FreeBSD 11.x.
Now  my driver takes only a few seconds to load and a few seconds to unload
in FreeBSD 12. BEta 3.

Hence it looks like the problem is with FreeBSD 11.x.
I am still waiting for  final release version of FreeBSD 12.0

Regards,
Steevan

On Tue, Nov 6, 2018 at 6:18 PM Stefan Esser <se at freebsd.org> wrote:

> Am 06.11.18 um 12:05 schrieb Steevan Rodrigues:
> > Thanks to all of you for the quick responses.
> >
> > I see this issue only  on a particular server.
> > I do not see this issue on another server with slightly older processor
> > Intel(R) Xeon(R) CPU E5-2620 v2 @ 2.10GHz  (dual socket 6 core per
> socket)
> > In this system the same program takes only about 800 usec
> >
> > I wonder whether it is problem with 11.x FreeBSD release on this
> particular
> > processor.
> > I came across two results (given below)  from Phoronix OSbench test suite
> > which also show poor thread creation time for FreeBSD 11.x
> >
> > https://openbenchmarking.org/result/1804094-AR-1804096AR58
> > https://openbenchmarking.org/result/1807114-RA-WINDOWSSE47
> >
> > In this look for "Create Threads"  row.
>
> This list shows, that FreeBSD-12 is fast, only FreeBSD-11 shows the long
> thread creation time (16000 vs 36 in whatever units), even though
> FreeBSD-12
> was running with KPTI-Patches.
>
> This lets me think that the issue that caused these delays has been fixed,
> but not merged to FreeBSD-11, yet.#
>
> I guess that the cause for the delays is the synchronization IPIs between
> sockets, and that these might be very high due to some cores in deep sleep
> modes (with corresponding long wake-up delays).
>
> Regards, STefan
>