Messages in this thread | | | Date | Mon, 19 Jun 2006 11:14:45 -0400 | From | Jeff Gold <> | Subject | Re: Serial Console and Slow SCSI Disk Access? |
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Helge Hafting wrote: > With nothing attached, any write to the serial device might go > through a lengthy timeout because of flow control. [...] But I can't > see why it'd make scsi disks slower. The scsi host adapter > initialization writes some messages of course, but there should be no > more console accesses during a hdparm test run.
This makes sense to me. When I attach a serial cable and use that to login (I've got agetty running), hdparm produces no console messages that I can see using minicom. Still, the disk throughput is around 1.5 MB/sec for some reason. When I disable the serial console in grub.conf and reboot I get over 70 MB/sec again.
A combination of out-of-tree patches (mainly network related but also one to disable PM_TIMERS) seem to eliminate the issue even with the serial console enabled, at least for the moment. That means I no longer have a problem, but the whole thing is mysterious to me.
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