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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Linux routing
On Wed, 22 May 2002 09:45:46 +0200, Peter van Dijk <[email protected]> said: > Why are you benchmarking network troughput by bzip2'ing a file in > /tmp? It makes no sense. I'm suspecting that he's trying to indirectly measure the kernel CPU usage. Most kernels don't give you the time spent in kernel mode (or bill it incorrectly to a process - I seem to remember some handwaving in either the Keifler&McKusic or Bach books about how interrupt time is charged against the current process, but it usually evens out in the end). So what you end up doing is running a cycle-sucking CPU-bound process, and seeing how much progress it makes - if in 60 seconds, the cycle sucker gets 45, then your kernel is getting the other 25% (or so the theory goes). It's not perfect, but it works as a back-of-envelope test and is probably accurate to within 5-10%... -- Valdis Kletnieks Computer Systems Senior Engineer Virginia Tech Attachment:
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