Re: [PATCH] CHECK_IRQ_PER_CPU() to avoid dead code in __do_IRQ()

[Karsten Wiese]

Am Montag, 8. August 2005 13:19 schrieb Alexander Nyberg:
> 
> There are many places where one could replace run-time tests with 
> #ifdef's but it makes reading more difficult (and in longer terms
> maintainence). Have you benchmarked any workload that benefits 
> from this?

Performance gain is small, but measurable: 0,02%
Tested on an Atlon64 running at 1000MHz.
I took this value from 9 runs (each with/without the patch) of 
	$ time lame x.wav
where each took about 1 minute.
3000 Interrupts/s were generated at the time by running
	$ jackd -R -dalsa -p64 -n2

0,02% really isn't that much....but Athlon64 is better than P4
with branch predictions, I think.

Erm... ok, I won't insist on having this patch applied ;-) 

   Karsten

	

	
		
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