Re: [Xen-devel] [PATCH V13 0/7] Mem_access for ARM

[Tamas K Lengyel <tklengyel@xxxxxxxxxxxxx>]

On Thu, Mar 12, 2015 at 12:30 PM, Ian Campbell <ian.campbell@xxxxxxxxxx> wrote:

On Fri, 2015-03-06 at 22:24 +0100, Tamas K Lengyel wrote:
> The ARM virtualization extension provides 2-stage paging, a similar mechanisms
> to Intel's EPT, which can be used to trace the memory accesses performed by
> the guest systems. This series sets up the necessary infrastructure in the
> ARM code to deliver the event on R/W/X traps. Finally, we turn on the
> compilation of mem_access and mem_event on ARM and perform the necessary
> changes to the tools side.
>
> This version of the series is based on master and each patch in the series has
> been compile tested on both ARM and x86.
>
> The following benchmarks have been completed on an Arndale board before and
> after applying this entire series in dom0, which had 2 vCPUs available
> pinned. No regressions are evident based on these benchmarks.
>
>Â Â Â Â Â Â Â Â Â Â Â Â Â| f0ffd60 | AFTER
> --------------------------------------------
> hackbench       Â| 1.604 Â| 1.618
> hackbench -pTÂ Â Â Â Â Â| 1.170Â Â| 1.126
> hardinfo CPU Blowfish Â| 43.252 | 43.323
> hardinfo CPU CryptoHash | 40.935Â | 40.893
> hardinfo CPU Fibonacci | 10.358 | 10.360
> hardinfo CPU N-Queens Â| 25.773 | 25.894
> hardinfo FPU FFTÂ Â Â Â | 20.332Â | 20.325
> hardinfo FPU Raytracing | 73.017Â | 73.104

Thanks for these, they are very reassuring.

More for curiosities sake than anything else: Do you have any figures
for the overhead of enabling memaccess?

I can gather some figures if needed but it is very use-case specific depending on which pages are being trapped and how.

Tamas

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel