> On Tue, 5 Oct 1999, John Hawkes wrote:
>
> > My test results:
...
> > With this workload on this 4xCPU Xeon hardware, spinlock contention
in
> > 2.2.10 consumed about 8% of theoretically available CPU cycles (340
> > millisecs/sec of waiting out of the 4,000 millisecs/sec
theoretically
> > available) vs. about 2% in 2.3.11 (95 millisecs of waiting out of
4,000
> > millisecs).
> >
> > The kernel_flag usage is still significant in 2.3, but its
contention is
> > greatly reduced. [...]
>
> have you checked out 2.3.18/19 already? Compared to 2.3.11 it has
fully
> threaded VFS, buffer-cache and VM, this should further cut down on
> kernel_flag usage. I suspect it should be well below 1% already.
For various reasons I haven't been able to rerun my tests with a
2.3.18/19 kernel on a 4xCPU system; but on a 2xCPU system, tests suggest
on the order of a 10% (YMMV) decrease in spinlock "wait time" cycles
between 2.3.16 and 2.3.18. That number may be wildly inaccurate, but at
least it's hinting that we're headed in the right direction.
-- John Hawkes http://oss.sgi.com
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