Messages in this thread | | | Date | Fri, 25 Jan 2002 18:10:12 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] syscall latency improvement #1 |
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Linus Torvalds wrote: > > It should be eminently testable. Just remove the cli from the standard > kernel, and do before-and-after tests. >
#include <unistd.h>
main() { int i = 100 * 1000 * 1000;
while (i--) getpid(); }
With cli: ./a.out 22.05s user 15.31s system 99% cpu 37.361 total
without cli: ./a.out 18.29s user 17.42s system 99% cpu 35.731 total
That's 4.6%. Intel P3.
It's also 306 cycles per iteration. So the cli added 14 cycles.
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