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Date: Fri, 5 Jun 2015 16:33:23 +0530
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From: Sai Prajeeth <csprajeeth@gmail.com>
Content-Type: multipart/alternative; boundary=001a1141c9b0a6d95b0517c33d28
Subject: [Qemu-devel] OpenBSD sched_yield() calls increase
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Hi list,

When running OpenBSD on QEMU without KVM, I see an increase in the number
of sched_yield() system calls in certain multi-threaded benchmarks
(sysbench). However while using KVM accelerator, the number of this system
calls is minimal. Does any have any insight why this is happening? The
execution of the benchmark is really slowed when not using KVM which is to
be expected but why is there such as massive increase in sched_yield system
calls? Moreover when using icount the number of sched_yield calls is
further increased.

Some Number:

With KVM accelerator - #of sched_yields = 500
Using TCG - #of sched_yields = 2600
Using icount - #of sched_yields = 16000

Anyone has an idea why this might be happening?

Thank you!

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Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr">Hi list,<div><br></div><div>When running OpenBSD on QEMU w=
ithout KVM, I see an increase in the number of sched_yield() system calls i=
n certain multi-threaded benchmarks (sysbench). However while using KVM acc=
elerator, the number of this system calls is minimal. Does any have any ins=
ight why this is happening? The execution of the benchmark is really slowed=
 when not using KVM which is to be expected but why is there such as massiv=
e increase in sched_yield system calls? Moreover when using icount the numb=
er of sched_yield calls is further increased.</div><div><br></div><div>Some=
 Number:</div><div><br></div><div>With KVM accelerator - #of sched_yields =
=3D 500</div><div>Using TCG - #of sched_yields =3D 2600</div><div>Using ico=
unt - #of sched_yields =3D 16000</div><div><br></div><div>Anyone has an ide=
a why this might be happening?</div><div><br></div><div>Thank you!</div><di=
v>=C2=A0=C2=A0</div></div>

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