Re: [PATCH 4/5] Powerpc/hw-breakpoint: Optimize disable path

On 6/18/19 11:45 AM, Michael Neuling wrote:

On Tue, 2019-06-18 at 09:57 +0530, Ravi Bangoria wrote:

quoted

Directly setting dawr and dawrx with 0 should be enough to
disable watchpoint. No need to reset individual bits in
variable and then set in hw.

This seems like a pointless optimisation to me. 

I'm all for adding more code/complexity if it buys us some performance, but I
can't imagine this is a fast path (nor have you stated any performance
benefits). 

This gets called from sched_switch. I expected the improvement when
we switch from monitored process to non-monitored process. With such
scenario, I tried to measure the difference in execution time of
set_dawr but I don't see any improvement. So I'll drop the patch.