On 04/07/2016 04:41 PM, Tejun Heo wrote:
Hello, Waiman.
On Thu, Apr 07, 2016 at 04:37:06PM -0400, Waiman Long wrote:
I would say that because I am lazy, I don't want compute the deltas every
time I want to see the effect of running a certain type of workload on the
statistics counts. I have use case that I need to track 10 or so statistics
counts and monitor their changes after running a job. It is much more
convenient to do a reset and see what you get than doing manual subtractions
to find out.
I don't know. Write a simple script? Even if you wanna keep it in
kernel, you can just have a base counter which offsets the summed up
value on read.
I had taken a look at percpu-refcount.[ch]. I think the synchronization code
is a bit overkill for this purpose as no one really need a very precise
statistics counts nor precise atomic reset. I would prefer providing an
optional atomic reset feature with slower statistics count update path for
the time being. If we come across a use case where we need atomic reset with
negligible slowdown, we could then refactor the code to use something
similar to what the percpu-refcount code is doing.
Please either drop reset or make it actually work; otherwise, I don't
think this should go in.
Thanks.
In this case, I think I will drop this reset functionality. It is not
really needed for this patchset.
Thanks for the feedback!
Cheers,
Longman
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