interrupt latency ?

From: SA (no_spam@ntlworld.com)
Date: Fri Feb 07 2003 - 13:50:52 EST


X-Status: S

Dear list,

What latency should I expect for hardware interrupts under k2.4 / i386 ?

ie how long should it take between the hardware signalling the interrupt and
the interrupt handler being called?

I am wrting a driver which pace IO with interrupts, generating one interrupt
for after every transfer is done. Looking at the hardware schematics the
interrupts should occur virtually instantly after each transfer but the
driver is waiting ~1ms/ interrupt.

I can use polling instead with busy waits but this seems a bit wasteful.

My interrupt is shared with my graphics card using the non-GPL nvidia driver -
could this be responsible for the delay (any experience with this)?

cat /proc/interrupts
.....
 10: 3028 XT-PIC eth0, VIA 82C686A
 11: 1117037 XT-PIC nvidia, PI stage <-- my driver
 12: 14776 XT-PIC usb-uhci, usb-uhci
.....

Thanks SA

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