alpha: add performance monitor interrupt counter
The following patches implement hardware performance events for the Alpha EV67 and later CPUs. I have had this running on a Compaq XP1000 (EV67, single CPU) for a few days now. Pretty cool -- discovered that the glibc exp2() library routine uses on average 985 cycles to execute 777 CPU instructions whereas Compaq's CPML library version of exp2() uses on average 32 cycles to execute 47 CPU instructions to achieve the same thing! This patch: Add performance monitor interrupt counternd and export the count to user space via /proc/interrupts. Signed-off-by: Michael Cree <mcree@orcon.net.nz> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jay Estabrook <jay.estabrook@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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