SMP overhead.

Rogier Wolff (R.E.Wolff@BitWizard.nl)
Wed, 13 Oct 1999 11:06:32 +0200 (MEST)

Every now and then the discussion about how much "penalty" we pay
for SMP support pops up. Turns out noone really knows.

Well, in the course of trying to find why interrupts were turned off
for so long sometimes, I found that a kernel compiled SMP takes 525
clocks (on a Pentium 120) to reach the interrupt routine. A non-smp
compiled kernel takes around 357 clocks.

Thanks to Andrea Arcangeli for the "lil" tool to measure this.

Roger.

-- 
** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 **
*-- BitWizard writes Linux device drivers for any device you may have! --*
------ Microsoft SELLS you Windows, Linux GIVES you the whole house ------




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