Re: Wierd context-switching issue on Xeon

Kenneth Marshall <ktm(at)is(dot)rice(dot)edu> writes:
> If the context swap storm derives from LWLock contention, maybe using
> a random order to assign buffer locks in buf_init.c would prevent
> simple adjacency of buffer allocation to cause the storm.

Good try, but no cigar ;-). The test cases I've been looking at take
only shared locks on the per-buffer locks, so that's not where the
context swaps are coming from. The swaps have to be caused by the
BufMgrLock, because that's the only exclusive lock being taken.

I did try increasing the allocated size of the spinlocks to 128 bytes
to see if it would do anything. It didn't ...

regards, tom lane