On Thu, Nov 16, 2023 at 12:53:55PM +0800, heqiong wrote:
> Reducing the impact of the cntvct_el0 register and isb() operation
> on microbenchmark test results to improve testing accuracy and reduce
> latency in test results.
>
> Signed-off-by: heqiong <heqiong1557@xxxxxxxxxxxxxx>
> ---
> arm/micro-bench.c | 19 +++++++++++--------
> 1 file changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/arm/micro-bench.c b/arm/micro-bench.c
> index fbe59d03..22408955 100644
> --- a/arm/micro-bench.c
> +++ b/arm/micro-bench.c
> @@ -24,7 +24,6 @@
> #include <asm/gic-v3-its.h>
> #include <asm/timer.h>
>
> -#define NS_5_SECONDS (5 * 1000 * 1000 * 1000UL)
> #define QEMU_MMIO_ADDR 0x0a000008
>
> static u32 cntfrq;
> @@ -346,17 +345,21 @@ static void loop_test(struct exit_test *test)
> }
> }
>
> - while (ntimes < test->times && total_ns.ns < NS_5_SECONDS) {
> - isb();
> - start = read_sysreg(cntvct_el0);
> + dsb(ish);
> + isb();
> + start = read_sysreg(cntvct_el0);
> + isb();
> + while (ntimes < test->times) {
> test->exec();
> - isb();
> - end = read_sysreg(cntvct_el0);
>
> ntimes++;
> - total_ticks += (end - start);
> - ticks_to_ns_time(total_ticks, &total_ns);
> }
> + dsb(ish);
> + isb();
> + end = read_sysreg(cntvct_el0);
> +
> + total_ticks = end - start;
> + ticks_to_ns_time(total_ticks, &total_ns);
>
> if (test->post) {
> test->post(ntimes, &total_ticks);
> --
> 2.39.3
>
Merged into https://gitlab.com/kvm-unit-tests/kvm-unit-tests master
Thanks,
drew
