On 10/17/18 12:47 PM, Aaron Lindsay wrote: > On Oct 16 17:04, Richard Henderson wrote: >> On 10/10/18 1:37 PM, Aaron Lindsay wrote: >>> + * Return the underlying cycle count for the PMU cycle counters. If we're >>> in >>> + * usermode, simply return 0. >>> + */ >>> +static uint64_t cycles_get_count(CPUARMState *env) >>> +{ >>> +#ifndef CONFIG_USER_ONLY >>> + return muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL), >>> + ARM_CPU_FREQ, NANOSECONDS_PER_SECOND); >>> +#else >>> + return 0; >>> +#endif >>> +} >> >> Usually we pass through the host cycle counter. >> See cpu_get_host_ticks(). > > Why do you prefer cpu_get_host_ticks()? And are you suggesting this for > just user-mode, or both system and user?
Just user-mode. Providing a clock with unknown scaling is more useful than a constant 0. r~