On Wed, 5 Jun 2019, Daniel Wagner wrote:
> CPUs such as Cortex-M8 don't have a rdtsc instruction. Fallback using
> a syscall.
>
> Signed-off-by: Daniel Wagner <wagi@xxxxxxxxx>
> ---
> src/queuelat/queuelat.c | 31 ++++++++++++++++++++++++++-----
> 1 file changed, 26 insertions(+), 5 deletions(-)
>
> diff --git a/src/queuelat/queuelat.c b/src/queuelat/queuelat.c
> index 3b291f168768..a5525e41776a 100644
> --- a/src/queuelat/queuelat.c
> +++ b/src/queuelat/queuelat.c
> @@ -7,6 +7,7 @@
> #include <stdio.h>
> #include <unistd.h>
> #include <signal.h>
> +#include <time.h>
>
> #define NSEC_PER_SEC 1000000000
>
> @@ -249,6 +250,8 @@ typedef unsigned long long cycles_t;
> typedef unsigned long long usecs_t;
> typedef unsigned long long u64;
>
> +#if defined __x86_64__ || defined __i386__
> +
> #ifdef __x86_64__
> #define DECLARE_ARGS(val, low, high) unsigned low, high
> #define EAX_EDX_VAL(val, low, high) ((low) | ((u64)(high) << 32))
> @@ -270,7 +273,25 @@ static inline unsigned long long __rdtscll(void)
> return EAX_EDX_VAL(val, low, high);
> }
>
> -#define rdtscll(val) do { (val) = __rdtscll(); } while (0)
> +#define gettick(val) do { (val) = __rdtscll(); } while (0)
> +
> +#elif defined __arm__
> +
> +static inline unsigned long long __clock_gettime(void)
> +{
> + struct timespec now;
> + int ret;
> +
> + ret = clock_gettime(CLOCK_MONOTONIC, &now);
> + if (ret < 0)
> + return 0;
> +
> + return now.tv_nsec;
> +}
> +
> +#define gettick(val) do { (val) = __clock_gettime(); } while (0)
> +
> +#endif
>
> static void init_buckets(void)
> {
> @@ -348,9 +369,9 @@ static void run_n(int n)
>
> memmove(dest, src, n);
> for (i = 0; i < loops; i++) {
> - rdtscll(b);
> + gettick(b);
> memmove(dest, src, n);
> - rdtscll(a);
> + gettick(a);
> delta = (a - b) * cycles_to_ns;
> account(delta);
> }
> @@ -446,9 +467,9 @@ void main_loop(void)
> int ret;
> int nr_packets_fill;
>
> - rdtscll(b);
> + gettick(b);
> memmove(dest, src, default_n);
> - rdtscll(a);
> + gettick(a);
> delta = (a - b) * cycles_to_ns;
> account(delta);
>
> --
Signed-off-by: John Kacur <jkacur@xxxxxxxxxx>
