On 28 Apr 2010, at 12:51, Steve Simon wrote:
Ok, I admit its a trivial experiment but:
fcp is still a 9p conversation. http get is a tcp stream. Fcp is
better than cp but not that much better.
If you're yanking one file, a TCP stream is pretty ideal. Dropping 9p
on top of it, even when the 9p involves multiple TREADs
in flight, is just making things slower.
larch% time cp /n/sources/extra/plan9.tar.bz2 /dev/null
0.02u 0.52s 647.90r cp /n/sources/extra/plan9.tar.bz2 /dev/null
larch% time fcp /n/sources/extra/plan9.tar.bz2 /dev/null
0.01u 0.85s 49.69r fcp /n/sources/extra/plan9.tar.bz2 /dev/null
larch% time hget http://plan9.bell-labs.com/sources/extra/plan9.tar.bz2
> /dev/null
0.37u 0.54s 32.84r hget
http://plan9.bell-labs.com/sources/extra/plan9.tar.bz2
Mmm, HTTP does give better performance, but its not that extreme,
and for a nightly cron script I would not worry about it.
I admit I am surprised by how much a difference there is, it should
be just Tread and Rread headers shouldn't it?
Could round-trip times be adding up? Does 9p do one file at once
strictly?
-Steve
--
Simplicity does not precede complexity, but follows it. -- Alan Perlis
