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
.~. 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
In response to
pgsql-performance by date
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