Re: 2.5.36-mm1 dbench 512 profiles

William Lee Irwin III (wli@holomorphy.com)
Fri, 20 Sep 2002 13:39:38 -0700


On Fri, Sep 20, 2002 at 11:51:13AM -0700, Hanna Linder wrote:
> I mentioned it at OLS too. It was the point of my talk. Next
> time I will request a non 10am time slot!

10AM is relatively early in the morning for me. =)

On Friday, September 20, 2002 05:03:58 -0700 William Lee Irwin III <wli@holomorphy.com> wrote:
>> take its place. Ugly. OTOH the qualitative difference is striking. The
>> interactive responsiveness of the machine, even when entirely unloaded,
>> is drastically improved, along with such nice things as init scripts
>> and kernel compiles also markedly faster. I suspect this is just the
>> wrong benchmark to show throughput benefits with.
>> Also notable is that the system time was significantly reduced though
>> I didn't log it. Essentially a long period of 100% system time is
>> entered after a certain point in the benchmark, during which there are
>> few (around 60 or 70) context switches in a second, and the duration
>> of this period was shortened.

On Fri, Sep 20, 2002 at 11:51:13AM -0700, Hanna Linder wrote:
> Bill, you are saying that replacing dcache_rcu significantly
> improved system response time among other things?
> Perhaps it is time to reconsider replacing fastwalk with dcache_rcu.
> Viro? What are your objections?

Basically, the big ones get laggy, and laggier with more cpus. This fixed
a decent amount of that.

Another thing to note is that the max bandwidth of these disks is 40MB/s,
so we're running pretty close to peak anyway. I need to either get an FC
cable or something to see larger bandwidth gains.

Cheers,
Bill
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