Re: [PATCH v2] arm64: Fix task tracing

From: Christopher Covington
Date: Wed Apr 10 2013 - 09:12:12 EST

Hi Will,

On 04/10/2013 07:41 AM, Will Deacon wrote:
> On Tue, Apr 09, 2013 at 01:33:34PM +0100, Christopher Covington wrote:
>> For accurate accounting pass contextidr_thread_switch the prev
>> task pointer, since cpu_switch_to has at that point changed the
>> the stack pointer.
>> Signed-off-by: Christopher Covington <cov@xxxxxxxxxxxxxx>
> Thanks Christopher -- I assume that using prev did resolve your issues?

Yes indeed. We're now able to see in simulation that if a userspace process
uses 100% CPU, its thread ID, rather than what was usually some random
kthread, gets written out most of the time. I donno if that meets your
criteria for a "real" use case, but I hope it's at least sufficient testing of
the code for now.


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