[dpdk-dev] [PATCH v5 1/2] test/power: add delay before checking cpuinfo cur freq
David Hunt
david.hunt at intel.com
Tue Apr 20 14:38:42 CEST 2021
On 15/4/2021 6:59 AM, Richael Zhuang wrote:
> For some platforms the newly-set frequency may not be effective
> immediately. If we didn't get the right value from cpuinfo_cur_freq
> immediately, add 10ms delay each time before rechecking until
> timeout.
>
> From our test, for some arm platforms, it requires up to 700ms when
> going from a minimum to a maximum frequency. And it's not the
> driver/software issue.
>
> Fixes: ed7c51a6a680 ("app/test: vm power management")
> Cc: alan.carew at intel.com
> Cc: stable at dpdk.org
>
> Signed-off-by: Richael Zhuang <richael.zhuang at arm.com>
> ---
> app/test/test_power_cpufreq.c | 27 ++++++++++++++++++++++-----
> 1 file changed, 22 insertions(+), 5 deletions(-)
>
> diff --git a/app/test/test_power_cpufreq.c b/app/test/test_power_cpufreq.c
> index 731c6b4dc..d47b3e0a1 100644
> --- a/app/test/test_power_cpufreq.c
> +++ b/app/test/test_power_cpufreq.c
> @@ -8,6 +8,7 @@
> #include <limits.h>
> #include <string.h>
> #include <inttypes.h>
> +#include <rte_cycles.h>
>
> #include "test.h"
>
> @@ -44,11 +45,13 @@ static int
> check_cur_freq(unsigned lcore_id, uint32_t idx)
> {
> #define TEST_POWER_CONVERT_TO_DECIMAL 10
> +#define MAX_LOOP 100
> FILE *f;
> char fullpath[PATH_MAX];
> char buf[BUFSIZ];
> uint32_t cur_freq;
> int ret = -1;
> + int i;
>
> if (snprintf(fullpath, sizeof(fullpath),
> TEST_POWER_SYSFILE_CUR_FREQ, lcore_id) < 0) {
> @@ -58,13 +61,27 @@ check_cur_freq(unsigned lcore_id, uint32_t idx)
> if (f == NULL) {
> return 0;
> }
> - if (fgets(buf, sizeof(buf), f) == NULL) {
> - goto fail_get_cur_freq;
> + for (i = 0; i < MAX_LOOP; i++) {
> + fflush(f);
> + if (fgets(buf, sizeof(buf), f) == NULL)
> + goto fail_all;
> +
> + cur_freq = strtoul(buf, NULL, TEST_POWER_CONVERT_TO_DECIMAL);
> + ret = (freqs[idx] == cur_freq ? 0 : -1);
> +
> + if (ret == 0)
> + break;
> +
> + if (fseek(f, 0, SEEK_SET) < 0) {
> + printf("Fail to set file position indicator to 0\n");
> + goto fail_all;
> + }
> +
> + /* wait for the value to be updated */
> + rte_delay_ms(10);
> }
> - cur_freq = strtoul(buf, NULL, TEST_POWER_CONVERT_TO_DECIMAL);
> - ret = (freqs[idx] == cur_freq ? 0 : -1);
>
> -fail_get_cur_freq:
> +fail_all:
> fclose(f);
>
> return ret;
Hi Richael
On your system, is the current cpu frequency found in cpuinfo_cur_freq
or in scaling_cur_freq? On my system, which uses intel_pstate driver,
there is no file called cpuinfo_cur_freq, but the test works when I
change TEST_POWER_SYSFILE_CUR_FREQ to scaling_cur_freq.
I know that's unrelated to your patch above, but it migth be worth using
a file common to all platforms, or else attempting to open one, and if
that fails, try open the other.
Rgds,
Dave.
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