File 0004-lparstat-Use-CLOCK_BOOTTIME-for-get_time-i... of Package powerpc-utils

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File 0004-lparstat-Use-CLOCK_BOOTTIME-for-get_time-interface-a.patch of Package powerpc-utils

From 9572f8c2022fed9783f0f606cbe778ffe0d93fef Mon Sep 17 00:00:00 2001
From: Shrikanth Hegde <sshegde@linux.ibm.com>
Date: Tue, 14 May 2024 20:46:44 +0530
Subject: [PATCH] lparstat: Use CLOCK_BOOTTIME for get_time interface and
 Deprecate get_sys_upttime

Upstream: merged, expected in v1.3.13
Git-commit: 9572f8c2022fed9783f0f606cbe778ffe0d93fef

"time" is used in lparstat.c to find the time elapsed either since boot
or between two intervals. But it is using gettimeofday which returns the
time elapsed since Epoch. This works for intervals calculations but it
doesn't work for since boot reports.

Instead use the CLOCK_BOOTTIME interface to get the elapsed time. This
fixes physc, utilization based on purr being wrong since boot.

Remove "uptime" interface since there are no users of it. One can get
the system uptime by calling "time" itself.

=============================== ::Test:: ==========================
reboot
stress-ng --cpu=$(nproc) -t 600
sleep 600

Results::
==================== Shared LPAR ==================================
System Configuration
type=Shared mode=Uncapped smt=8 lcpu=12 mem=15573440 kB cpus=37 ent=12.00

lparstat -E			<-- Observe utilization values
====== 6.9-rc1 and lparstat 1.3.10 =============
---Actual---                 -Normalized-
%busy  %idle   Frequency     %busy  %idle
------ ------  ------------- ------ ------
  0.00   0.00  3.87GHz[106%]   0.00   0.00

==== With this patch and patch 2/3 =============
---Actual---                 -Normalized-
%busy  %idle   Frequency     %busy  %idle
------ ------  ------------- ------ ------
 38.72   0.11  3.87GHz[106%]  41.04   0.12

lparstat				<-- Observe physc values
====== 6.9-rc1 and lparstat 1.3.10  ===================================
%user  %sys %wait    %idle    physc %entc lbusy   app  vcsw phint
----- ----- -----    -----    ----- ----- ----- ----- ----- -----
47.48  0.01  0.00    52.51     0.00  0.00 47.49 69099.72 541547    21

=== With this patch and this patch ================================ ===
%user  %sys %wait    %idle    physc %entc lbusy   app  vcsw phint
----- ----- -----    -----    ----- ----- ----- ----- ----- -----
47.48  0.01  0.00    52.51     5.73 47.75 47.49 31.21 541753    21

==================== Dedicated LPAR ==================================
System Configuration
type=Dedicated mode=Capped smt=8 lcpu=12 mem=15573248 kB cpus=0 ent=12.00

::lparstat -E::			<-- Observe utilization values.
======= 6.9-rc1 and lparstat 1.3.10 =============
---Actual---                 -Normalized-
%busy  %idle   Frequency     %busy  %idle
------ ------  ------------- ------ ------
  0.00   0.00  3.87GHz[106%]   0.00   0.00

=== With this patch and powerpc-utils patch to do the above equation ===
---Actual---                 -Normalized-
%busy  %idle   Frequency     %busy  %idle
------ ------  ------------- ------ ------
 48.87  51.51  3.87GHz[106%]  51.81  54.60

::lparstat::				<-- Observe physc values.
======= 6.9-rc1 and lparstat 1.3.10 =============
%user  %sys %wait    %idle    physc %entc lbusy   app  vcsw phint
----- ----- -----    -----    ----- ----- ----- ----- ----- -----
48.38  0.01  0.00    51.61     0.03  0.25 48.39  0.00 344661     8

=== With this patch and powerpc-utils patch to do the above equation ===
%user  %sys %wait    %idle    physc %entc lbusy   app  vcsw phint
----- ----- -----    -----    ----- ----- ----- ----- ----- -----
48.38  0.01  0.00    51.61    12.05 100.42 48.39  0.00 344877     8

=============================================================================

Interval based lparstat values are same. With this patch the physc and
busy purr/idle purr values show correctly for since boot reports.

Note: this patch doesn't fix the idle purr being incorrect. That is
currently being investigated.

Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
---
 src/lparstat.c | 57 +++++++++-----------------------------------------
 src/lparstat.h |  6 ------
 2 files changed, 10 insertions(+), 53 deletions(-)

diff --git a/src/lparstat.c b/src/lparstat.c
index 30889b2..3e9169d 100644
--- a/src/lparstat.c
+++ b/src/lparstat.c
@@ -36,6 +36,7 @@
 #include "lparstat.h"
 #include "pseries_platform.h"
 #include "cpu_info_helpers.h"
+#include <time.h>
 
 #define LPARCFG_FILE	"/proc/ppc64/lparcfg"
 #define SE_NOT_FOUND	"???"
@@ -255,14 +256,17 @@ long long get_delta_value(char *se_name)
 
 void get_time()
 {
-	struct timeval t;
 	struct sysentry *se;
+	struct timespec ts;
+	int err;
 
-	gettimeofday(&t, 0);
+	err = clock_gettime(CLOCK_BOOTTIME, &ts);
+	if (err)
+		return;
 
 	se = get_sysentry("time");
 	sprintf(se->value, "%lld",
-		(long long)t.tv_sec * 1000000LL + (long long)t.tv_usec);
+		(long long)ts.tv_sec);
 }
 
 int get_time_base()
@@ -304,7 +308,6 @@ double get_scaled_tb(void)
 	online_cores = atoi(se->value);
 
 	elapsed = get_delta_value("time");
-	elapsed = elapsed / 1000000.0;
 
 	se = get_sysentry("timebase");
 	timebase = atoi(se->value);
@@ -312,31 +315,6 @@ double get_scaled_tb(void)
 	return (timebase * elapsed) * online_cores;
 }
 
-void get_sys_uptime(struct sysentry *unused_se, char *uptime)
-{
-	FILE *f;
-	char buf[80];
-
-	f = fopen("/proc/uptime", "r");
-	if (!f) {
-		fprintf(stderr, "Could not open /proc/uptime\n");
-		sprintf(uptime, SE_NOT_VALID);
-		return;
-	}
-
-	if ((fgets(buf, 80, f)) != NULL) {
-		char *value;
-
-		value = strchr(buf, ' ');
-		*value = '\0';
-		sprintf(uptime, "%s", buf);
-	} else {
-		sprintf(uptime, SE_NOT_VALID);
-	}
-
-	fclose(f);
-}
-
 int get_nominal_frequency(void)
 {
 	FILE *f;
@@ -403,13 +381,12 @@ void get_cpu_physc(struct sysentry *unused_se, char *buf)
 	delta_purr = get_delta_value("purr");
 
 	se = get_sysentry("tbr");
-	if (se->value[0] != '\0') {
+	if (se->old_value[0] != '\0') {
 		delta_tb = get_delta_value("tbr");
 
 		physc = delta_purr / delta_tb;
 	} else {
 		elapsed = get_delta_value("time");
-		elapsed = elapsed / 1000000.0;
 
 		se = get_sysentry("timebase");
 		timebase = atoi(se->value);
@@ -436,23 +413,9 @@ void get_cpu_app(struct sysentry *unused_se, char *buf)
 {
 	struct sysentry *se;
 	float timebase, app, elapsed_time;
-	long long new_app, old_app, delta_time;
-	char *descr, uptime[32];
+	long long new_app, old_app;
 
-	se = get_sysentry("time");
-	if (se->old_value[0] == '\0') {
-		/* Single report since boot */
-		get_sysdata("uptime", &descr, uptime);
-
-		if (!strcmp(uptime, SE_NOT_VALID)) {
-			sprintf(buf, "-");
-			return;
-		}
-		elapsed_time = atof(uptime);
-	} else {
-		delta_time = get_delta_value("time");
-		elapsed_time = delta_time / 1000000.0;
-	}
+	elapsed_time = get_delta_value("time");
 
 	se = get_sysentry("timebase");
 	timebase = atof(se->value);
diff --git a/src/lparstat.h b/src/lparstat.h
index 77203e1..86e45e4 100644
--- a/src/lparstat.h
+++ b/src/lparstat.h
@@ -60,7 +60,6 @@ extern void get_cpu_stat(struct sysentry *, char *);
 extern void get_cpu_physc(struct sysentry *, char *);
 extern void get_per_entc(struct sysentry *, char *);
 extern void get_cpu_app(struct sysentry *, char *);
-extern void get_sys_uptime(struct sysentry *, char *);
 extern void get_cpu_util_purr(struct sysentry *unused_se, char *buf);
 extern void get_cpu_idle_purr(struct sysentry *unused_se, char *buf);
 extern void get_cpu_util_spurr(struct sysentry *unused_se, char *buf);
@@ -272,11 +271,6 @@ struct sysentry system_data[] = {
 	{.name = "phint",
 	 .descr = "Phantom Interrupts"},
 
-	/* /proc/uptime */
-	{.name = "uptime",
-	 .descr = "System Uptime",
-	 .get = &get_sys_uptime},
-
 	/* /sys/devices/system/cpu/cpu<n>/ */
 	/* Sum of per CPU SPURR registers */
 	{.name = "spurr",
-- 
2.45.2

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