On Fri, Jun 01, 2012 at 11:00:57PM +0400, Alexey I. Froloff wrote:
On Fri, Jun 01, 2012 at 01:50:55PM -0500, Michael Cronenworth wrote:
> Not a single person who has claimed a performance or semantic win for
> this /tmp move has replied when asked for proof.
$ time dd if=/dev/zero of=/tmp/file bs=1M count=10240
10240+0 records in
10240+0 records out
10737418240 bytes (11 GB) copied, 4.95536 s, 2.2 GB/s
dd if=/dev/zero of=/tmp/file bs=1M count=10240 0.00s user 3.44s system 69% cpu 4.956
total
No visual shanges in system behavior.
I assume that your /tmp is on tmpfs; on all of *my* computers this
command would fail because the tmpfs would be too limited to store a
10GB file.
$ time dd if=/dev/zero of=/var/tmp/file bs=1M count=10240
10240+0 records in
10240+0 records out
10737418240 bytes (11 GB) copied, 59.2188 s, 181 MB/s
dd if=/dev/zero of=/var/tmp/file bs=1M count=10240 0.00s user 54.26s system 91% cpu
59.239 total
SSD disk. System becomes unresponsive for a couple of tens of seconds.
No problem here. The machine isn't being unresponsive.
$ time dd if=/dev/zero of=$HOME/file bs=1M count=10240
10240+0 records in
10240+0 records out
10737418240 bytes (11 GB) copied, 75.1548 s, 143 MB/s
dd if=/dev/zero of=$HOME/file bs=1M count=10240 0.01s user 71.30s system 94% cpu 1:15.16
total
SATA disk. System becomes less responsive for a couple of seconds.
I can't reproduce this. System works fine for me.
Rich.
--
Richard Jones, Virtualization Group, Red Hat
http://people.redhat.com/~rjones
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