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2004.09.17 02:58 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
On Thu, 16 Sep 2004, Bob Friesenhahn wrote: > I have attached source for a small test program I used to see how systems > behave under load when using memory mapped files. Naturally, documentation > is poor and the code is meant for hacking. :-) Here are some results just obtained from running the mmap file update benchmark on some modern systems with fast CPUs and fast disks. Maybe someone can modify the benchmark to use stdio or read/write and see how performance compares with mmap? Solaris 9: % time ./mmaptest 16 File length = 6442450941 Stride = 131072 ./mmaptest 16 4.92s user 50.81s system 44% cpu 2:06.55 total Linux 2.6.7: % time ./mmaptest 16 File length = 6442450941 Stride = 65536 ./mmaptest 16 2.54s user 13.28s system 11% cpu 2:17.95 total FreeBSD 5.0: % time ./mmaptest 16 File length = 6442450941 Stride = 65536 ./mmaptest 16 4.12s user 76.41s system 35% cpu 3:46.18 total ====================================== Bob Friesenhahn bfriesen@simple.dallas.tx.us http://www.simplesystems.org/users/bfriesen