Messages in this thread | | | Date | Sat, 23 Feb 2008 13:31:00 +0100 | From | Andi Kleen <> | Subject | Re: [PATCH [RT] 08/14] add a loop counter based timeout mechanism |
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> *) compute the context-switch pair time average for the system. This is > your time threshold (CSt).
This is not a uniform time. Consider the difference between context switch on the same hyperthread, context switch between cores on a die, context switch between sockets, context switch between distant numa nodes. You could have several orders of magnitude between all those.
> > *) For each lock, maintain an average hold-time (AHt) statistic (I am > assuming this can be done cheaply...perhaps not).
That would assume that the hold times are very uniform. But what happens when you e.g. have a workload where 50% of the lock aquisitions are short and 30% are long?
I'm a little sceptical of such "too clever" algorithms.
-Andi
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