Re: [Xen-devel] xen-unstable, winxp32 very poor performance on AMD FX-8150, I bisected and changeset is 24770:7f79475d3de7

[Peter Maloney <peter.maloney@xxxxxxxxxxxxxxxxxxxx>]

On 11/13/2012 02:17 PM, Peter Maloney wrote:
> On 2012-11-01 18:28, Andres Lagar-Cavilla wrote:
>> On Nov 1, 2012, at 1:00 PM, Tim Deegan <tim@xxxxxxx> wrote:
>>
>>> Hi,
>>>
>>> At 14:59 +0100 on 22 Oct (1350917960), Tim Deegan wrote:
>>>> At 19:21 +0200 on 20 Oct (1350760876), Peter Maloney wrote:
>>>>> The change was 8 months ago
>>>>>
>>>>> changeset:   24770:7f79475d3de7
>>>>> user:        Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>
>>>>> date:        Fri Feb 10 16:07:07 2012 +0000
>>>>> summary:     x86/mm: Make p2m lookups fully synchronized wrt modifications
>>> [...]
>> Not any immediate ideas without profiling.
>>
>> However, most callers of hvmemul_do_io pass a stub zero ram_gpa address. We 
>> might be madly hitting the p2m locks for no reason there.
>>
>> How about the following patch, Peter, Tim?
>

I tried the patch applied to xen-unstable 4.2.0-branched
528f0708b6db+ 4.2.0-branched

It seemed the same. It was extremely slow with 7 vcpus, and with 2 vcpus
it was slow, but fast enough that I could bother to log in and out
during the test.

Attached are logs generated with this command (using xm instead of xl):
for i in {1..30}; do xm debug-keys d; xm dmesg -c; done >> nameoflog

xenxp_xm_dmesg_-c_7cpus_idle.log
xenxp_xm_dmesg_-c_7cpus_logintooslow.log
xenxp_xm_dmesg_-c_7cpus_shutdown.log
xenxp_xm_dmesg_-c_duringlogin.log
xenxp_xm_dmesg_-c_idling_login_screen.log

Also there is xenxp_dmesg.log which is output from hitting alt+sysrq+w
and p in case it's relevant.

BTW this time I am testing with kernel 3.6.7

Attachment: xenxp_logs.tgz
Description: application/compressed-tar

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