Messages in this thread | | | Date | Mon, 6 Oct 2014 10:16:28 -0500 (CDT) | From | Christoph Lameter <> | Subject | Re: Why do we still have 32 bit counters? Interrupt counters overflow within 50 days |
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On Mon, 6 Oct 2014, Thomas Gleixner wrote:
> So if you want to fix that as well, you really need to think about the > 32 bit case because there is no serialization for the interrupts which > are delivered directly from their own vector. And no, we should not > diverge 32 and 64 bit artificially here simply because the same 50 > days wrap applies to both.
Is it a divergence if both 64bit and 32 bit are unsing unsigned long?
> > I really start to wonder whether all this is worth the trouble. It has > been this way forever and 1k timer interrupts per second is not really > a new thing either. So we did not change anything which suddenly makes > tools confused.
Tools expect the number of interrupt to increase linearly and not jump by 2^32 once in awhile. There are functions in the kernel (/proc/stat) that sum up various interrupt counters and that are types unsigned long. These larger numbers can suddenly jump by 2^32. Its pretty unusual for a 64 bit conter to do that and it requires some head scratching until we figured that one out.
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