Emmanuel Ackaouy wrote:
> If you have access to the Xen console, can you send output of
> the 'r' (runq) key while your domains are each getting 50% of
> CPU? Just take a few snapshots a few seconds apart. That would
> confirm the theory.
Sorry, but i dunno how to do that? Can you give me a hint?
> Also, setting cap=100 on a UP guest is pointless. Just leave it
> as zero. A VCPU isn't going to get more than 100% of a physical
> CPU anyway.
Yepp, you are right. The reason i have done this was 'cause i want
to demonstrate the credit-scheduler.
If both domains have one vcpu, managed by Xen and i set the following:
Domain-0:~ # xm sched-credit -d xendom1
{'cap': 100, 'weight': 200}
Domain-0:~ # xm sched-credit -d xendom2
{'cap': 100, 'weight': 100}
Both domain are running at 100 percent cpu, but on different pcpus.
That is correct, but does not demonstrate how to use the credit scheduler.
Ok, the other advice from Atsushi was to give one domain two vcpus, the other
one vcpu,
both with the same weight and all vcpus pinned to the same pcpu. That does not
help
either. Both domains are still running at 50 percent.
Even if i set the weight of xendom1, resp. xendom2 to be twice as the value
of xendom2, resp. xendom1, i get the same result.
Here is what i have done:
Domain-0:~ # xm vcpu-list
Name ID VCPU CPU State Time(s) CPU Affinity
Domain-0 0 0 1 --- 46.1 any cpu
Domain-0 0 1 1 r-- 28.5 any cpu
xendom1 1 0 0 r-- 558.7 0
xendom2 3 0 0 -b- 21.6 0
xendom2 3 1 0 --- 256.0 0
Domain-0:~ # xm sched-credit -d xendom1
{'cap': 0, 'weight': 256}
Domain-0:~ # xm sched-credit -d xendom2
{'cap': 0, 'weight': 256}
3 domains: 2 running, 0 blocked, 0 paused, 0 crashed, 0 dying, 0 shutdown
Mem: 2612284k total, 2603856k used, 8428k free CPUs: 2 @ 2992MHz
NAME STATE CPU(sec) CPU(%) MEM(k) MEM(%) MAXMEM(k) MAXMEM(%)
VCPUS NETS NETTX(k) NETRX(k) VBDS VBD_OO VBD_RD VBD_WR SSID
Domain-0 -----r 85 1.6 2048256 78.4 no limit n/a
2 4 163 139 0 0 0 0 0
xendom1 ------ 566 49.0 262144 10.0 532480 20.4
1 1 5 29 2 0 10 539 0
xendom2 -----r 285 51.0 262144 10.0 262144 10.0
2 1 6 17 2 0 4622 1772 0
Greetings,
-timo
> On Feb 1, 2007, at 10:47, Timo Benk wrote:
>> 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
>>
>>
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>> http://lists.xensource.com/xen-devel
>>
>
--
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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