Re: Firewire/USB Card for Qube 2

--- Izumi Tsutsui <[email protected]> wrote:

> [email protected] wrote:
> 
> > Speaking of speeds, frequencies and bandwidths
> seems
> > that regardless of the speed of the Ethernet
> adapters
> > the Qube 2 can not go beyond 10MBits/s speed.
> 
> How did you measure the speed?
> ttcp on my RaQ (not RaQ2) shows:
> ---
> # uname -v
> NetBSD 4.99.63 (GENERIC) #83: Sat May 24 01:56:56
> JST 2008  \
>
tsutsui@mirage:/usr/src/sys/arch/cobalt/compile/GENERIC
> # ttcp -rs
> ttcp-r: buflen=8192, nbuf=2048, align=16384/0,
> port=5001  tcp
> ttcp-r: socket
> ttcp-r: accept from 192.168.20.1
> ttcp-r: 16777216 bytes in 6.39 real seconds =
> 2562.00 KB/sec +++
> ttcp-r: 2051 I/O calls, msec/call = 3.19, calls/sec
> = 320.72
> ttcp-r: 0.0user 2.6sys 0:06real 41% 0i+0d 0maxrss
> 0+2pf -15+45csw
> # ttcp -ts 192.168.20.1
> ttcp-t: buflen=8192, nbuf=2048, align=16384/0,
> port=5001  tcp  -> 192.168.20.1
> ttcp-t: socket
> ttcp-t: connect
> ttcp-t: 16777216 bytes in 7.20 real seconds =
> 2276.17 KB/sec +++
> ttcp-t: 2048 I/O calls, msec/call = 3.60, calls/sec
> = 284.52
> ttcp-t: 0.0user 5.1sys 0:07real 71% 0i+0d 0maxrss
> 0+2pf -12+51csw
> # 
> ---
> so at least it's faster than 10Mb/s ;-)
> 
> > Is it possible that they is not performing up to
> their
> > specification because of low bus frequency,
> > competitions or slow IRQ response?
> 
> There is some implementation issue (there are too
> many extra
> cache flush, tulip Ethernet doesn't handle unaligned
> RX buffer etc.),
> but a slower IDE disk/interface might be most
> problematic on usual ops.
> 
> Some extra kernel options (DIAGNOSTIC, DEBUG,
> LOCKDEBUG, KMEMSTATS etc)
> also make kernel much slower, BTW.
> ---
> Izumi Tsutsui
> 

Sorry for the delayed reply... I did not test with
ttcp or any other tool. I actually timed the transfers
when I noticed it is slower than I expected.

I also did wget of a large file (DVD iso image) from a
linux box. In the same network (100 MBit switch and
infrastructure) I managed to squeeze about 11.5
MBytes/s between the Linux boxes on average (which is
normal), but only about 750-800 KBytes/s between the
Qube 2 and a Linux box.

And that was freezing the kernel at some point when I
reported it (in our prior exchange).

Further tests between a Windows box and a Linux box
the speed in this network can reach only 2.4 MBytes/s
and it is the winsock and the Windows kernel to blame
for that, but the funny part is that between a Windows
(XP) box and the Qube 2 the speed is proportionally
slower than between a Linux box and the Qube 2.
Meaning it goes with not more than 350-400 KBytes/s
real transfer. I will give this credit to Windows,
because I noticed that the collision packets are very
often when Windows is involved. Just tcpdump it and
you will see.

Puzzling, isn't it? And I do not have time (or
knowledge) to track the things down the chain for this
slowdown.