Messages in this thread | | | Subject | Re: [PATCH 1/5] ftrace: Synchronize variable setting with breakpoints | From | Steven Rostedt <> | Date | Thu, 31 May 2012 16:40:33 -0400 |
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On Thu, 2012-05-31 at 16:37 -0400, Steven Rostedt wrote: > On Thu, 2012-05-31 at 22:26 +0200, Peter Zijlstra wrote: > > > Right, but when you loose stop-machine you could simply do 30k > > kmap_atomic/kunmap_atomic's consecutively since you're not holding > > anybody up. > > It requires 3 IPIs per update too. Thus that's 90,000 IPIs you are > blasting^Wsending to all CPUs. >
Note, currently ftrace adds breakpoints to all locations, sends out the IPIs, modifies the code, sends out the IPIs and then removes the breakpoint, sends out the IPIs.
Just three IPIs for those 30,000 updates.
-- Steve
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