[Beowulf] Re: Re: Home beowulf - NIC latencies
lindahl at pathscale.com
Thu Feb 10 18:36:20 PST 2005
On Thu, Feb 10, 2005 at 01:35:06PM -0700, Maurice Hilarius wrote:
> Further, all of these lovely benchmarks lack one really important detail:
> Comparisons between different interfaces and drivers MUST show CPU usage
> while running them.
No. If you want to look at that, run a real application and watch the
wall time. It's extremely hard to get a good estimate of cpu usage out
of a microbenchmark, and running "top" or /bin/time to do it is
> If I have a fantastic device that uses infinitely small time (latency)
> and moves huge amounts of data (bandwidth) but in doing so it takes 80%
> of a CPU, we do not have a useful solution..
If large cpu usage is a problem, it will show up nicely in real
> What we all need is some form of useful standardized benchmarks that
> looks like real world code from a number of different disciplines, that
> we can use to test the hardware, so we may compare results in a
> meaningful manner.
Amen. So use the MM5 t3a benchmark, maybe even SPEC HPC, the canned
benchmarks for Amber, Charmm, DL_POLY, etc. The NAS Parallel
Benchmarks are also good, they are much closer to real apps than
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