[Samba] Performance with XP64
glenn at zewt.org
Tue Mar 15 14:35:32 MDT 2011
On Tue, Mar 15, 2011 at 3:36 PM, Volker Lendecke
<Volker.Lendecke at sernet.de>wrote:
> On Tue, Mar 15, 2011 at 02:28:37PM -0400, Glenn Maynard wrote:
> > tcpdump reading a 256MB file (from tmpfs) on XP64:
> > http://zewt.org/~glenn/samba.tcpdump.gz, 56M/sec
> That's pretty much what you would expect. The trace shows
> that your program reads sequentially in 61k chunks. Given
My program reads in 1M chunks; it's the OS splitting apart the reads.
that your network latency is roughly 600 microseconds,
gives 55MB/sec. You might want to try smbclient, that does
> larger parallel reads, or a copy program that uses multiple
> threads simultaneously.
That's what I'd expect if things are as broken as they look from that dump:
the client (XP) isn't buffering requests at all, so the window caps out at
64k. The mail from earlier suggests that some people get much better
speed from other servers (though without enough information to really be
useful). I don't know the protocol, so I can't tell if there's something
preventing the client from buffering multiple read requests, for example,
which I'd expect of any network FS.
Multiple threads isn't a good solution (at these speeds, it's liable to
severely hurt streaming performance), and in any case it doesn't help actual
use, with real applications.
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