Ravikiran G Thirumalai wrote:

On Sat, Jan 13, 2007 at 03:39:45PM +1100, Nick Piggin wrote:

quoted

What is the "CS time"?

Critical Section :).  This is the maximal time interval I measured  from 
t2 above to the time point we release the spin lock.  This is the hold 
time I guess.

quoted

It would be interesting to know how long the maximal lru_lock *hold* time 
is,
which could give us a better indication of whether it is a hardware problem.

For example, if the maximum hold time is 10ms, that it might indicate a
hardware fairness problem.

The maximal hold time was about 3s.

Well then it doesn't seem very surprising that this could cause a 30s wait
time for one CPU in a 16 core system, regardless of fairness.

I guess most of the contention, and the lock hold times are coming from
vmscan? Do you know exactly which critical sections are the culprits?

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