Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 19 Jul 2018 08:08:20 -0700 | Subject | Re: [PATCH 08/10] psi: pressure stall information for CPU, memory, and IO |
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On Wed, Jul 18, 2018 at 5:03 AM Peter Zijlstra <peterz@infradead.org> wrote: > > And as said before, we can compress the state from 12 bytes, to 6 bits > (or 1 byte), giving another 11 bytes for 59 bytes free. > > Leaving us just 5 bytes short of needing a single cacheline :/
Do you actually need 64 bits for the times?
That's the big cost. And it seems ridiculous, if you actually care about size.
You already have a 64-bit start time. Everything else is some cumulative relative time. Do those really need 64-bit and nanosecond resolution?
Maybe a 32-bit microsecond would be ok - would you ever account more than 35 minutes of anything without starting anew?
Linus
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