qemu+aio vs C2

Andriy Gapon avg at icyb.net.ua
Thu Feb 26 08:31:43 PST 2009

on 26/02/2009 18:27 Paul B. Mahol said the following:
> On 2/26/09, Andriy Gapon <avg at icyb.net.ua> wrote:
>> I see something unusual and surprising for me: if I kldload aio for qemu's
>> sake
>> and then actually start qemu, I see that share of C2 in cx_usage is
>> constantly
>> dropping and then finally there is "too many short sleeps, backing off to
>> C1".
>> This is on i386 with stable/7 as of r188116.
>> I am out of ideas.
> And qemu guest is?
> Perhaps you should try changing guest kern.hz sysctl setting.
> I dont think related comitt got MFC-ed to STABLE.

For what I've been doing the guest was our boot code and loader. Nothing beyond that.
And, pardon me, how guest software could affect host's hardware in this way?
As i understand only a hardware even of some sort could interrupt C2.

Andriy Gapon

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