On 08/26/2010 12:43 AM, Glauber Costa wrote:
This patch proposes a common steal time implementation. When no
steal time is accounted, we just add a branch to the current
accounting code, that shouldn't add much overhead.
When we do want to register steal time, we proceed as following:
- if we would account user or system time in this tick, and there is
out-of-cpu time registered, we skip it altogether, and account steal
time only.
- if we would account user or system time in this tick, and we got the
cpu for the whole slice, we proceed normaly.
- if we are idle in this tick, we flush out-of-cpu time to give it the
chance to update whatever last-measure internal variable it may have.
This approach is simple, but proved to work well for my test scenarios.
in a UP guest on UP host, with a cpu-hog in both guest and host shows
~ 50 % steal time. steal time is also accounted proportionally, if
nice values are given to the host cpu-hog.
A cpu-hog in the host with no load in the guest, produces 0 % steal time,
with 100 % idle, as one would expect.
The scheduler people and lkml need to be copied on this patch.
Since s390 does steal time (I think?), can this code be shared?
--
error compiling committee.c: too many arguments to function
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