Re: sd_mod load is delayed.

[Hai Zaar <haizaar@gmail.com>]

>
> On Sunday 29 January 2006 13:12, Andrey Borzenkov wrote:
> > As far as I can tell, SCSI subsystem is using scan mutex; so only one HBA
> > can do scanning at a time. Or so it appears. May be LSI is the frst one to
> > kick in.
>
> Oops sorry ignore this, what I meant is per-host mutex.
Anyway, it does not seem to  help.
Here are some numbers.
Working directory is /sys/bus/pci/devices.
  0000:00:1f.2 is SATA controller (ata_piix modalias)
  0000:02:09.0 is LSI logic controller (mptspi modalias)
Each command was run by /bin/bash, that was spawned right after 'udev
--deamon' in initramfs. After each command, the system was rebooted:

Emitting only SATA event
    echo add > 0000:00:1f.2/uevent; time while ! grep -q sda
/proc/partitions; do sleep 0.1; done
    real 0m0.209sec
    -----------------------------

Emitting both SATA and LSI events
    echo add > 0000:00:1f.2/uevent; echo add > 0000:02:09.0; time
while ! grep -q sda /proc/partitions; do sleep 0.1; done
    real 0m12.244s
    -----------------------------
As you may see there is significant increase. The same happens if we
use regular trigger_device_events function:
    trigger_device_events; time while ! grep -q sda /proc/partitions;
do sleep 0.1; done
    real 0m13.605sec
    -----------------------------
Now, if we run modprobe ourselves, it takes no time again!
    modprobe mptspi & modprobe ata_piix & time while ! grep -q sda
/proc/partitions; do sleep 0.1; done
    real 0m0.210s

Can anyone explain this?

--
Zaar


-------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc. Do you grep through log files
for problems?  Stop!  Download the new AJAX search engine that makes
searching your log files as easy as surfing the  web.  DOWNLOAD SPLUNK!
http://sel.as-us.falkag.net/sel?cmd_______________________________________________
Linux-hotplug-devel mailing list  http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel