Messages in this thread | | | Date | Wed, 10 Sep 2003 23:35:15 +0200 | From | Pavel Machek <> | Subject | Re: Efficient IPC mechanism on Linux |
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Hi!
> > Can you make it available so we can test on, say, 900MHz athlon? Or > > you can have it tested on 1800MHz athlon64, that's about as high end > > as it can get. > > I just deleted the program, so here's a rewrite :) > > #include <sys/mman.h> > > int main() > { > int i, j; > for (j = 0; j < 64; j++) { > volatile char * ptr = > mmap (0, 4096 * 4096, PROT_READ | PROT_WRITE, > MAP_PRIVATE | MAP_ANON, -1, 0); > for (i = 0; i < 4096; i++) { > #if 1 > *(ptr + 4096 * i) = 0; /* Write */ > #else > (void) *(ptr + 4096 * i); /* Read */ > #endif > } > munmap ((void *) ptr, 4096 * 4096); > } > return 0; > } > > Smallest results, from "gcc -o test test.c -O2; time ./test" on a > 1500MHz dual Athlon 1800 MP: > > Write: > real 0m1.316s > user 0m0.059s > sys 0m1.256s > > ==> 7531 cycles per page > > Read: > real 0m0.199s > user 0m0.053s > sys 0m0.146s > > ==> 1139 cycles per page > > As I said, it's a crude upper bound.
But you should also time memory remapping stuff on same cpu, no?
Pavel -- When do you have a heart between your knees? [Johanka's followup: and *two* hearts?] - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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