[Xen-devel] Credit Scheduler not working correct (3.0.4-0)

[Timo Benk <timo.benk@xxxxxx>]

Hi,

on my system, it seems that the credit scheduler does not work as expected. The
problem seems to be related to HyperThreading, if i switch off HT in the BIOS
Setup, the scheduler works as expected.

I have two domains running, both pinned to the same processor:

Domain-0:~ # xm vcpu-list
Name                              ID  VCPU   CPU State   Time(s) CPU
Affinity
Domain-0                           0     0     1   ---      30.2 any cpu
Domain-0                           0     1     1   r--      12.0 any cpu
xendom1                            1     0     0   ---      98.6 0
xendom2                            2     0     0   r--     110.3 0

Both domains should consume max. 100 Percent of that processor, but
xendom1 has a weight twice as big as xendom2:

Domain-0:~ # xm sched-credit -d xendom1
{'cap': 100, 'weight': 200}
Domain-0:~ # xm sched-credit -d xendom2
{'cap': 100, 'weight': 100}

In my understanding of the credit scheduler, xendom1 should get twice as
much CPU-time as xendom2. But:

xentop - 11:05:46   Xen 3.0.4-0
Mem: 2612284k total, 2603852k used, 8432k free    CPUs: 2 @ 2992MHz
      NAME  STATE   CPU(sec) CPU(%)  [...]
  Domain-0 -----r         42    0.6  [...]
   xendom1 ------        122   49.8  [...]
   xendom2 -----r        133   50.2  [...]

As you can see, both domains got an equal amount of the CPU.

Am i missing something or do i understand something wrong?

Greetings,
-timo
-- 
Timo Benk - Jabber ID: fry@xxxxxxxxxxxx - ICQ ID: #414944731
PGP Public Key: http://m28s01.vlinux.de/timo_benk_gpg_key.asc


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