Re: [PATCH] ia64: disable preemption in udelay()

From: Christian Hildner
Date: Fri Dec 16 2005 - 03:19:41 EST


Luck, Tony schrieb:

Moving the current slim-line udelay() out of line would save 41 Kbytes
of text in the generic vmlinux, plus making any modules that use
udelay smaller too. Savings run from a 128-160 bytes for drivers
with just one call to a max of 9 Kbytes for qla2xxx.ko.

Tony,

we should really take the chance to make the kernel smaller since we don't have to become active to make it bigger. This happens every day by itself. Furthermore I'd guess that for the current and future IA64 implementations we might even win performance by having functions out of line since we have a really fast call mechanism here. Of course any difference heavily depends on the cache utilization so there would be some benchmark needed. At least for the udelay the answer is easy and must be "do it out of line".

Did anyone already run a benchmark for comparison of inline vs. out of line for IA64? Or does anybody want to do it?

Christian

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