Re: Serial Console and Slow SCSI Disk Access?

Mark Lord
2006-06-12T21:39:43Z

Jeff Gold wrote:
> Does it make sense that enabling a serial console would reduce the
> bandwidth of a SCSI disk by more than a factor of ten? This seems crazy
> to me but there's no arguing with empirical facts. I have an IBM x345
> system on which I installed an unmodified 2.6.16.20 kernel built with
> gcc-4.0.2-8.fc4 (the kernel configuration file I used can be found at
> http://augart.com/jgold/kconfig). With the control kernel command line
> I get about 70 MB/sec with hdparm -t but when I add "console=ttyS0,9600
> console=tty0" I get about 1.6 MB/sec instead.

This can happen if there are kernel messages being printed on the serial console.
If all is quiet, I would expect things to be as fast as normal elsewhere.

-ml