Messages in this thread |  | | Date | Wed, 11 Oct 2000 21:04:07 -0400 (EDT) | From | Alexander Viro <> | Subject | Re: test9 not using buffers |
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On Thu, 12 Oct 2000, Tom Holroyd wrote:
> Alpha DP264 (UP), SCSI, floppy > > If I do a dd if=/dev/zero of=/tmp/moo count=100000, I don't see any > increase in buffers, as reported by vmstat. Furthermore, if I read from > /dev/fd0, it used to buffer the whole thing, so a second read would be > fast -- now it hits the floppy again. >
a) /dev/zero: character device, no buffers used at all. /tmp/moo: regular file, data goes into pagecache, so all buffers you will get out of it will be for indirect blocks. Assuming 4Kb filesystem that would be about 13Kb worth. Userland buffer is in pagecache too, indeed.
b) invalidate on last close.
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