SMT being hyperthreading, right? Do the default conf files in ./config/
have SMT enabled? If not, then yes, I have seen this in non-SMT
configurations. Though I typically see this problem only at high core
counts. I rarely see it happens at 8 cores or less.


On Fri, Dec 6, 2013 at 9:40 AM, <[email protected]> wrote:

> I'm experiencing this problem with newer, untested versions of qemu as
> well. I've only seen it happen with SMT configurations, however -- have
> either of you seen it without SMT?
>
> Tyler
>
> > We sometimes had this happen too, but I think no one has found a reliable
> > way to figure out where the problem happens.
> >
> > When you say 'never', how long have you waited for it? In my experience
> > sometimes when this happens, it can stay in kernel mode a long long time
> > but then eventually come back to user space.
> >
> >
> > On Wed, Dec 4, 2013 at 10:27 PM, Hongsun An <[email protected]> wrote:
> >
> >> Hello,
> >>
> >> I'm using marss86+dramsim2
> >> I made a checkpoint of sphinx3 after fastfowarding 10 billions
> >> instructions
> >> and simulated the checkpoint.
> >>
> >> here is the middle of the log
> >>
> >> Completed    1060261000 cycles,     415478808 commits:    940320 Hz,
> >> 332565 insns/sec: rip 000000000041e5cf
> >> Completed    1060450000 cycles,     415546041 commits:    940386 Hz,
> >> 334523 insns/sec: rip 000000000041e5cf
> >> Completed    1060633000 cycles,     415610543 commits:    912773 Hz,
> >> 321725 insns/sec: rip 0000000000402a25
> >> Completed    1060811000 cycles,     415672043 commits:    889292 Hz,
> >> 307255 insns/sec: rip 0000000000415c42
> >> Completed    1061031000 cycles,     415712907 commits:   1099278 Hz,
> >> 204185 insns/sec: rip ffffffff8105f411
> >> Completed    1061175000 cycles,     415825905 commits:    715988 Hz,
> >> 561841 insns/sec: rip ffffffff810c043a
> >> Completed    1061237000 cycles,     416011905 commits:    307139 Hz,
> >> 921417 insns/sec: rip ffffffff810c043a
> >> Completed    1061299000 cycles,     416197905 commits:    306858 Hz,
> >> 920576 insns/sec: rip ffffffff810c043a
> >> Completed    1061361000 cycles,     416383905 commits:    306683 Hz,
> >> 920050 insns/sec: rip ffffffff810c043a
> >> .......
> >> .......
> >> user.base_machine.ooo_0_0.thread0.commit.ipc = 0.391764
> >> kernel.base_machine.ooo_0_0.thread0.commit.ipc = 2.99783
> >> total.base_machine.ooo_0_0.thread0.commit.ipc = 2.29421
> >>
> >> At some point, rip is changed to ffffffff810c043a and never turns back
> >> to
> >> 0x000000000xxxxx.
> >> Every benchmark has simliar result.
> >>
> >> I simulated soplex, libquantum with test input and they worked well.
> >> What I was missing..
> >>
> >>
> >>
> >> _______________________________________________
> >> http://www.marss86.org
> >> Marss86-Devel mailing list
> >> [email protected]
> >> https://www.cs.binghamton.edu/mailman/listinfo/marss86-devel
> >>
> >>
> > _______________________________________________
> > http://www.marss86.org
> > Marss86-Devel mailing list
> > [email protected]
> > https://www.cs.binghamton.edu/mailman/listinfo/marss86-devel
> >
>
>
>
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