[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH] roughly synchronize calibration calls to reduce skew
This patch (based from 18139) roughly synchronizes calls to local_time_calibration() across multiple processors by setting each next timer to a "round epoch". This results in reduced skew; both max and average skew are reduced by between a factor of 2 and 3. Note that timers still fire at slightly different times because the next "round epoch" is still relative to local stime which still has some inter-processor skew. Making local_time_calibration() precisely concurrent across processors is a possible next step but since each processor still has to get the platform timer -- an operation that is locked and takes several (and sometimes tens of) microseconds, concurrency will take some more cleverness. Signed-off-by: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx> =================================== Thanks... for the memory I really could use more / My throughput's on the floor The balloon is flat / My swap disk's fat / I've OOM's in store Overcommitted so much (with apologies to the late great Bob Hope) Attachment:
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