On Fri, Dec 19, 2014 at 11:51 AM, Linus Torvalds
<torva...@linux-foundation.org> wrote:
>
> I do note that we depend on the "new mwait" semantics where we do
> mwait with interrupts disabled and a non-zero RCX value. Are there
> possibly even any known CPU errata in that area? Not that it sounds
> likely, but still..
Remind me what CPU you have in that machine again? The %rax value for
the mwait cases in question seems to be 0x32, which is either C7s-HSW
or C7s-BDW, and in both cases has the "TLB flushed" flag set.
I'm pretty sure you have a Haswell, I'm just checking. Which model?
I'm assuming it's family 6, model 60, stepping 3? I found you
mentioning i5-4670T in a perf thread.. That the one?
Anyway, I don't actually believe in any CPU bugs, but you could try
"intel_idle.max_cstate=0" and see if that makes any difference, for
example.
Or perhaps just "intel_idle.max_cstate=1", which leaves intel_idle
active, but gets rid of the deeper sleep states (that incidentally
also play games with leave_mm() etc)
Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
