[dpdk-stable] patch 'power: fix current frequency index' has been queued to stable release 19.11.6

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to stable release 19.11.6

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 10/30/20. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Thanks.

Luca Boccassi

---
>From 6e2760a68cd64d05b6cc82185b7ec00d3fb5b9d9 Mon Sep 17 00:00:00 2001
From: Reshma Pattan <reshma.pattan at intel.com>
Date: Wed, 29 Jul 2020 14:58:53 +0100
Subject: [PATCH] power: fix current frequency index

[ upstream commit a3f9cca718d75f2d60f5895be94f0f14e5fc4865 ]

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")

Signed-off-by: Reshma Pattan <reshma.pattan at intel.com>
Reviewed-by: Liang Ma <liang.j.ma 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 2d8a9499dc..fa16b44146 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
@@ -531,6 +534,57 @@ out:
 	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_init(unsigned int lcore_id)
 {
@@ -571,6 +625,11 @@ power_pstate_cpufreq_init(unsigned int lcore_id)
 		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) {
-- 
2.20.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2020-10-28 10:35:15.268005980 +0000
+++ 0113-power-fix-current-frequency-index.patch	2020-10-28 10:35:11.668832438 +0000
@@ -1,8 +1,10 @@
-From a3f9cca718d75f2d60f5895be94f0f14e5fc4865 Mon Sep 17 00:00:00 2001
+From 6e2760a68cd64d05b6cc82185b7ec00d3fb5b9d9 Mon Sep 17 00:00:00 2001
 From: Reshma Pattan <reshma.pattan at intel.com>
 Date: Wed, 29 Jul 2020 14:58:53 +0100
 Subject: [PATCH] power: fix current frequency index
 
+[ upstream commit a3f9cca718d75f2d60f5895be94f0f14e5fc4865 ]
+
 During power initialization the pstate cpufreq api is
 not setting the initial curr_idx of pstate_power_info
 to corresponding current frequency index.
@@ -34,7 +36,6 @@
 now with the new changes.
 
 Fixes: e6c6dc0f ("power: add p-state driver compatibility")
-Cc: stable at dpdk.org
 
 Signed-off-by: Reshma Pattan <reshma.pattan at intel.com>
 Reviewed-by: Liang Ma <liang.j.ma at intel.com>
@@ -43,10 +44,10 @@
  1 file changed, 59 insertions(+)
 
 diff --git a/lib/librte_power/power_pstate_cpufreq.c b/lib/librte_power/power_pstate_cpufreq.c
-index e3126d3754..edf6328e5f 100644
+index 2d8a9499dc..fa16b44146 100644
 --- a/lib/librte_power/power_pstate_cpufreq.c
 +++ b/lib/librte_power/power_pstate_cpufreq.c
-@@ -51,6 +51,9 @@
+@@ -52,6 +52,9 @@
  		} \
  } while (0)
  
@@ -112,9 +113,9 @@
 +}
 +
  int
- power_pstate_cpufreq_check_supported(void)
+ power_pstate_cpufreq_init(unsigned int lcore_id)
  {
-@@ -586,6 +640,11 @@ power_pstate_cpufreq_init(unsigned int lcore_id)
+@@ -571,6 +625,11 @@ power_pstate_cpufreq_init(unsigned int lcore_id)
  		goto fail;
  	}