[dpdk-stable] [PATCH] power: fix current frequency index
Liang, Ma
liang.j.ma at intel.com
Fri Jul 31 11:32:26 CEST 2020
Hi Reshma,
I'm OK with the change. That's the missing part about init process.
Reviewed-by Liang Ma <liang.j.ma at intel.com>
Regards
Liang
On 29 Jul 14:58, Reshma Pattan wrote:
> 1)
> During power initialization the pstate cpufreq api is
> not setting the initial curr_idx of pstate_power_info
> to corresponding current frequency index.
>
> Without this the idx is always 0, which is causing the
> below check to pass and returns without setting the initial
> min/max frequency to system max frequency and this leads to
> incorrect frequency settings when power_pstate_cpufreq_set_freq()
> is called in the apps.
>
> set_freq_internal(struct pstate_power_info *pi, uint32_t idx)
> {
> ...
>
> /* Check if it is the same as current */
> if (idx == pi->curr_idx)
> return 0;
> ...
> }
>
> scenario 1:
> If system has starting scaling min/max: 1000/1000, and want to
> set this to 2200/2200, the max frequency gets updated but not min.
>
> scenario 2:
> If system has starting scaling min/max: 2200/1000, and want to set
> to 2200/2200, the max, min frequency was not updated. Since no change
> in max that should be ok, but min was also ignored, which will be fixed
> now with the new changes.
>
> Fixes: e6c6dc0f ("power: add p-state driver compatibility")
> Cc: stable at dpdk.org
> CC: liang.j.ma at intel.com
> Signed-off-by: Reshma Pattan <reshma.pattan at intel.com>
> ---
> lib/librte_power/power_pstate_cpufreq.c | 59 +++++++++++++++++++++++++++++++++
> 1 file changed, 59 insertions(+)
>
> diff --git a/lib/librte_power/power_pstate_cpufreq.c b/lib/librte_power/power_pstate_cpufreq.c
> index 2526441..262f024 100644
> --- a/lib/librte_power/power_pstate_cpufreq.c
> +++ b/lib/librte_power/power_pstate_cpufreq.c
> @@ -52,6 +52,9 @@
> } \
> } while (0)
>
> +/* macros used for rounding frequency to nearest 100000 */
> +#define FREQ_ROUNDING_DELTA 50000
> +#define ROUND_FREQ_TO_N_100000 100000
>
> #define POWER_CONVERT_TO_DECIMAL 10
> #define BUS_FREQ 100000
> @@ -532,6 +535,57 @@ struct pstate_power_info {
> return ret;
> }
>
> +static int
> +power_get_cur_idx(struct pstate_power_info *pi)
> +{
> + FILE *f_cur;
> + int ret = -1;
> + char *p_cur;
> + char buf_cur[BUFSIZ];
> + char fullpath_cur[PATH_MAX];
> + char *s_cur;
> + uint32_t sys_cur_freq = 0;
> + unsigned int i;
> +
> + snprintf(fullpath_cur, sizeof(fullpath_cur),
> + POWER_SYSFILE_CUR_FREQ,
> + pi->lcore_id);
> + f_cur = fopen(fullpath_cur, "r");
> + FOPEN_OR_ERR_RET(f_cur, ret);
> +
> + /* initialize the cur_idx to matching current frequency freq index */
> + s_cur = fgets(buf_cur, sizeof(buf_cur), f_cur);
> + FOPS_OR_NULL_GOTO(s_cur, fail);
> +
> + p_cur = strchr(buf_cur, '\n');
> + if (p_cur != NULL)
> + *p_cur = 0;
> + sys_cur_freq = strtoul(buf_cur, &p_cur, POWER_CONVERT_TO_DECIMAL);
> +
> + /* convert the frequency to nearest 100000 value
> + * Ex: if sys_cur_freq=1396789 then freq_conv=1400000
> + * Ex: if sys_cur_freq=800030 then freq_conv=800000
> + * Ex: if sys_cur_freq=800030 then freq_conv=800000
> + */
> + unsigned int freq_conv = 0;
> + freq_conv = (sys_cur_freq + FREQ_ROUNDING_DELTA)
> + / ROUND_FREQ_TO_N_100000;
> + freq_conv = freq_conv * ROUND_FREQ_TO_N_100000;
> +
> + for (i = 0; i < pi->nb_freqs; i++) {
> + if (freq_conv == pi->freqs[i]) {
> + pi->curr_idx = i;
> + break;
> + }
> + }
> +
> + fclose(f_cur);
> + return 0;
> +fail:
> + fclose(f_cur);
> + return ret;
> +}
> +
> int
> power_pstate_cpufreq_check_supported(void)
> {
> @@ -578,6 +632,11 @@ struct pstate_power_info {
> goto fail;
> }
>
> + if (power_get_cur_idx(pi) < 0) {
> + RTE_LOG(ERR, POWER, "Cannot get current frequency "
> + "index of lcore %u\n", lcore_id);
> + goto fail;
> + }
>
> /* Set freq to max by default */
> if (power_pstate_cpufreq_freq_max(lcore_id) < 0) {
> --
> 1.8.3.1
>
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