On Fri, Oct 2, 2015 at 9:56 AM, Peter Maydell <peter.mayd...@linaro.org> wrote: > On 2 October 2015 at 17:44, Christopher Covington <c...@codeaurora.org> wrote: >> I've sent out the CPI test case and while exercising it I noticed that >> Laurent's patch fixed -icount. So my original goal has been accomplished. I'm >> happy to rebase this patch if the authorities (Peter Maydell?) think using >> cpu_get_ticks() is the right thing to do. Otherwise I'll probably try to move >> on to support for the instructions event in the ARM PMU. > > Authority here is probably Peter Crosthwaite. I can produce an > opinion but I'd have to go and research a bunch of stuff to do > that, so I'm hoping to avoid it... >
So my idea here is the CPU input frequency should be a property of the CPU. Some experimental results confirm that the PMCCNTR on many common ARM implementations is directly connected to the input clock and can be relied on as a straight free-running counter. I think a genuine instruction counter is something else and this timer should be independent of any core provider of cycle count. Regards, Peter > thanks > -- PMM
