Scott Carey wrote:
But back on topic for HT -- HT doesn't like spin-locks much unless they
use the right low level instruction sequence rather than actually
spinning. With the right instruction, the spin will allow the other
thread to do work... With the wrong one, it will tie up the pipeline. I
have no idea what Postgres' spin-locks and tool chain compile down to.
I have two hyperthreaded Xeon processors, so this machine thinks it has four
processors. I have not seen the effect of spin locks with postgres. But I
can tell that Firefox and Thunderbird use the wrong ones. When one of these
is having trouble accessing a site, the processor in question goes up to
100% and the other part of the hyperthreaded processor does nothing even
though I run four BOINC processes that would be glad to gobble up the
cycles. Of course, since it is common to both Firefox and Thunderbird,
perhaps it is a problem in the name server, bind. But wherever it is, it
bugs me.
--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 13:55:01 up 6 days, 3:52, 3 users, load average: 4.03, 4.25, 4.45
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