Messages in this thread | | | Date | Tue, 14 Jun 2016 18:36:01 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH V4] irq: Track the interrupt timings |
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On Tue, 14 Jun 2016, Nicolas Pitre wrote: > On Tue, 14 Jun 2016, Daniel Lezcano wrote: > > If the storage is a bit larger (let's say 16 values) and there is no memset > > and the sum is not computed, at least we need a count for the number of values > > in the array before this one is fulfilled, otherwise the statistics will be > > wrong as we will take into account the entire array with old values, no ? > > The point is not to change from 8 to 16 entries, but to store raw 64-bit > timestamps instead of computed 32-bit deltas. Whether or not those > timestamps are too far apart and discarded can be done at idle entry > time.
Correct, and you don't have to know how many timestamps are in the array simply because if it is cleared at init time, then any not yet set value will create a large gap, which you filter out.
The point is to make the fast path overhead as small as possible. And if that's just a store and index increment, then it can be inline and not a function call.
Thanks,
tglx
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