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Linux.com: Benchmarking the Linux Kernel: An Interview with Professor Randy Appleton

Sep 09, 2001, 14:11 (39 Talkback[s])
"Consider the fork() system call. We benchmarked it, and found that as everyone thought, it takes a long time and is expensive. That's bad, but probably unavoidable. The Apache people already knew this, and therefore go to trouble and expense to avoid forking when possible. They changed their algorithms and wrote code to avoid fork, when that programmer time could have been used for other interesting stuff. Of course they cannot avoid fork entirely. Further, no one knows how much cost they pay by avoiding it when possible. So it's hard to know the true cost of fork for something as common as Apache.

Now what about Windows? Windows doesn't have fork(), and they don't even have anything totally like fork(). So how do we compare the fork() time we measured in Linux to anything in Windows? We cannot.

Further, the difference between Linux and Windows has forced Apache and IIS to use different algorithms, so even they're hard to compare.

In general, when it is possible to compare some function that both have, Linux does well. It does not always win, but it wins often. Reading a file is an example of functionality that both operating systems have."

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