FYI, please see attached patch. On Mon, Mar 28, 2016 at 6:32 PM, ron minnich <[email protected]> wrote:
> The timing is per-operation, not per total run. Even if we get one timer > interrupt in there, it's going to be one bad data point. I'm fine with > that. > > But, me, i'm only taking 128 samples. I think that's more the enough and > it runs in maybe several dozen microseconds. > > ron > > On Mon, Mar 28, 2016 at 3:29 PM ron minnich <[email protected]> wrote: > >> I'm still testing on linux. Akaros comes later :-) >> >> On Mon, Mar 28, 2016 at 2:59 PM Barret Rhoden <[email protected]> >> wrote: >> >>> On 2016-03-28 at 21:46 ron minnich <[email protected]> wrote: >>> > https://github.com/akaros/fputest >>> > >>> > >>> > We're getting there. It's now using gcc intrinsics, which hopefully >>> > are more correct. Still trying to get sane timing for the "no op" >>> > case. >>> >>> i'd be concerned if the intrinsics are right and our own versions are >>> wrong. hopefully that won't be the case after this gets sorted out. >>> >>> >>> given that n = 1000000 and rdtsc alone takes O(30) ticks, you're >>> probably getting interference from the timer IRQ, even on Akaros Core 0. >>> here's two quick things to try: >>> >>> call uthread_mcp_init() somewhere in main. that'll make you an MCP. >>> it's a bit hacky. verify that it's working with a ps or pip. >>> >>> check your tsc overhead against __procinfo.timing_overhead or against >>> the console output during boot, e.g. >>> >>> TSC overhead (Min: 32, Max: 36) >>> >>> i didn't look at any of the actual FPU stuff for issues yet. >>> >>> barret >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Akaros" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> To post to this group, send email to [email protected]. >>> For more options, visit https://groups.google.com/d/optout. >>> >> -- > You received this message because you are subscribed to the Google Groups > "Akaros" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Akaros" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. For more options, visit https://groups.google.com/d/optout.
0001-Changed-rdtsc-and-rdtscp-as-per-Intel-benchmarking-w.patch
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