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Re: bad performance
- To: misc_(_at_)_openbsd_(_dot_)_org
- Subject: Re: bad performance
- From: Roland Dowdeswell <elric_(_at_)_imrryr_(_dot_)_org>
- Date: Thu, 21 Nov 2002 06:00:26 -0500
- Organization: The Fall of Imrryr
2002-11-20 21:55:40, Fabian Duelli wrote:
>I've setted up an OpenBSD 3.2 i386 FTP server. (ftpd -DllUSA)
>Compiled my own kernel with
>NMBCLUSTERS=8192 (100 MBit network)
>BUFCACHEPERCENT=80 (384 MB RAM)
>but now my problem is when I'm copying files from
>the server I don't get more than 1.5 MByte/s.
>The same when I'm uploading anything.
>For testing I've downloaded the same file (60 MB)
>several times but I didn't get more speed.
>(Because the file should than be in the RAM)
>The server runs also as NFS server and
>I don't get more than 1.5 MByte/s too.
>The network is ok, I own another BSD box (FreeBSD)
>and there I get more than 5 MByte/s.
What you want to determine is where the bottleneck is. You've
mentioned two tests here, FTP and NFS. Both of them involve disk
and network operations. So, you should come up with tests that
isolate the two subsystems to see where the 1.5MB/s is coming from.
For the fs, just dd(1) the file a few times to /dev/null with a
reasonable block size and see how it performs. For the network,
well, try ftp'ing from a memory filesystem. That'll give you much
more insight into where the performance limitations are.
Also, keep in mind that increasing the number of bufpages may not
help ftpd as it mmap(2)s the file and OpenBSD does not have UBC.
In fact, increasing BUFCACHEPERCENT to 80 may be actively hurting
Roland Dowdeswell http://www.Imrryr.ORG/~elric/