Re: [ANNOUNCE] [PATCHES] Advanced TCA Hotswap Support in Linux Kernel

Michael Clark
2002-10-16T00:59:29Z

On 10/16/02 04:46, Steven Dake wrote:
> The data/telecoms I've talked to require disk hotswap times of less then
> 20 msec from notification of hotwap to blue led (a light used to
> indicate the device can be removed). They would like 10 msec if it
> could be done. This is because of how long it takes on a surprise
> extraction for the hardware to send the signal vs the user to disconnect
> the hardware.

I'm just surprised that the SAF-TE processers will respond this quickly.

> For legacy systems such as SAFTE hotswap, polling through sg at 10 msec
> intervals would be extremely painful because of all the context
> switches. A timer scheduled every 10 msec to send out a SCSI message
> and handle a response if there is a hotswap event is a much better course.

100 context switchs a second isn't that much is it?

I'll adjust safte-monitor from its default 2 second polling down
to 10msec and see what the result is.

~mc