Re: [9fans] Is this Plan9 performance, Ok

[erik quanstrom <quanstro@quanstro.net>]

On Thu Apr  9 05:18:31 EDT 2009, bdheeman@gmail.com wrote:
> Extraction of only a 180M archive knelled down a 1.8Ghz/P-M4/i686/1Gb
> RAM/40GiB IDE HDD machine running vanilla Plan9 installed natively:
>
> term% cat /dev/sdC0/ctl |grep dma
> config 0040 capabilities 2F00 dma 00550020 dmactl 00550020 rwm 8 rwmctl 0
> term% time /n/mon/mnt/sda9/Downloads/Plan9/mroot-linuxemu.tbz2
> ...
> 183.27u 31.06s 623.86r   tar zxf
> /n/mon/mnt/sda9/Downloads/Plan9/mroot-linuxemu.tbz2
> term% ls -l /n/mon/mnt/sda9/Downloads/Plan9/mroot-linuxemu.tbz2
> --rw-rw-r-- M 47 root wheel 188569960 Apr  8 16:15

a laptop drive of that general description is probablly good for 20mb/s
sequential io.  assuming that the uncompressed archive is 3x larger,
you're getting about 1mb/s writes even with the slow decompression.

it looks like that archive is pulled over the network.  since you have
a 3c905, that would be at a maximum of about 10mb/s.  if you're
linked at 10mb/s, the limit is about 1mb/s.

i'd recommend checking the drive's speed with dd.
	time dd -if /dev/sdC0/data -of /dev/null -count 5000 -bs 64k

i don't recall if the 3c905 will tell you its link speed.  you can
try /dev/kmesg or /net/ether0/ifstats under mbps.  the latter may be
the maximum mbps the card is capable of, due to the fact mbps is
used to size queues.

i like the suggestion to time pulling down the archive and sending it
to /dev/null.  since you have enough memory.  you could seperately
time extracting it to ramfs.

> Moreover, it is strange that Plan9 running under QEMU on 2.4Ghz/Core2
> Duo/2Gb RAM/250GiB SATA/IDE HDD machine out performs a natively
> installed one.

what is slower, exactly?

- erik