Messages in this thread |  | | | Date | Sat, 17 Apr 1999 19:22:25 +0200 (MEST) | | From | Walter Hofmann <> | | Subject | Re: Solaris tmpfs vs. Linux RAMdisk |
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-----BEGIN PGP SIGNED MESSAGE----- On Sat, 17 Apr 1999, Jim Nance wrote:
> On Fri, Apr 16, 1999 at 09:46:09PM +0200, Walter Hofmann wrote: > > I get the following results: > > > > wh@frodo:~ > ./test /home/wh > > Did 14137 loops in 2.99 seconds (4724.35 loops/sec) > > wh@frodo:~ > ./test /tmp > > Did 15923 loops in 2.99 seconds (5322.36 loops/sec) > > wh@frodo:~ > ./test /usr/local/tmp > > Did 28783 loops in 3.00 seconds (9596.10 loops/sec) > > > > /home and /tmp are on the same ext2 partition (486M, 84% filled) > > /usr is an (soft-)raid0 array (4G, 81% filled, 2 disks) > > > > There is virtually no disk access during the test, the results are stable > > over many runs. > > > > Yet there is one big question: Why is the raid0-array twice as fast when > > there is no disk access??? > > The number of files in the directory definitly makes a difference. This is > because the kernel has to look through all the directory entries to make > sure the file does not already exist. Could this be it?
wh@frodo:~/programming/testing > gcc -O3 tmpfs.c -o tmpfs wh@frodo:~/programming/testing > mkdir /home/wh/newdir wh@frodo:~/programming/testing > ./tmpfs /home/wh/newdir/ Did 26071 loops in 3.00 seconds (8692.22 loops/sec) wh@frodo:~/programming/testing > mkdir /usr/local/tmp/newdir wh@frodo:~/programming/testing > ./tmpfs /usr/local/tmp/newdir/ Did 32696 loops in 3.00 seconds (10912.29 loops/sec) wh@frodo:~/programming/testing > mkdir /tmp/newdir wh@frodo:~/programming/testing > ./tmpfs /tmp/newdir/ Did 25906 loops in 3.00 seconds (8643.41 loops/sec) This seems to explain the difference between /home/wh and /tmp, which are both on the same partition. But the RAID0 array /usr is still faster.
Walter
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