powerpc-utils/SOURCES/0013-lparstat-Add-support-for-cpu-hotplug.patch
2021-11-25 11:51:14 +00:00

178 lines
4.5 KiB
Diff

From 179d461b79387bd3877cd239da933a8dfceae05c Mon Sep 17 00:00:00 2001
Message-Id: <179d461b79387bd3877cd239da933a8dfceae05c.1587532692.git.kamalesh@linux.vnet.ibm.com>
In-Reply-To: <cover.1587532692.git.kamalesh@linux.vnet.ibm.com>
References: <cover.1587532692.git.kamalesh@linux.vnet.ibm.com>
From: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Date: Tue, 21 Apr 2020 08:23:24 -0500
Subject: [PATCH V4 13/14] lparstat: Add support for cpu-hotplug
To: powerpc-utils-devel@googlegroups.com
Cc: Tyrel Datwyler <tyreld@linux.ibm.com>,
Nathan Lynch <nathanl@linux.ibm.com>,
Naveen N . Rao <naveen.n.rao@linux.vnet.ibm.com>,
Gautham R . Shenoy <ego@linux.vnet.ibm.com>,
Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
For optimizing the read of sysfs file, the file descriptors are
assigned at the beginning of the run but they do not change dynamically
in event of a cpu hotplug, resulting under-estimated load average in
case of new cpus onlined or error in case of cpu removed. This can be
solved by checking for the online cpus every interval and re-assign
the file descriptors again with new set of cpu on hotplug event.
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
---
src/lparstat.c | 78 +++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 71 insertions(+), 7 deletions(-)
diff --git a/src/lparstat.c b/src/lparstat.c
index 5390b9f..51caa3d 100644
--- a/src/lparstat.c
+++ b/src/lparstat.c
@@ -21,6 +21,7 @@
* @author Nathan Fontenot <nfont@linux.vnet.ibm.com>
*/
+#define _GNU_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
@@ -28,6 +29,7 @@
#include <getopt.h>
#include <unistd.h>
#include <fcntl.h>
+#include <sched.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/time.h>
@@ -47,6 +49,7 @@ static int cpus_in_system;
static int threads_in_system;
static cpu_sysfs_fd *cpu_sysfs_fds;
+static cpu_set_t *online_cpus;
struct sysentry *get_sysentry(char *name)
{
@@ -180,7 +183,7 @@ int parse_sysfs_values(void)
if (rc == -1) {
fprintf(stderr, "Failed to /sys/devices/system/cpu/cpu%d/spurr\n",
cpu_sysfs_fds[i].cpu);
- goto error;
+ goto check_cpu_hotplug;
}
value = strtoll(line, NULL, 16);
@@ -190,7 +193,7 @@ int parse_sysfs_values(void)
if (rc == -1) {
fprintf(stderr, "Failed to /sys/devices/system/cpu/cpu%d/idle_purr\n",
cpu_sysfs_fds[i].cpu);
- goto error;
+ goto check_cpu_hotplug;
}
value = strtoll(line, NULL, 16);
@@ -200,7 +203,7 @@ int parse_sysfs_values(void)
if (rc == -1) {
fprintf(stderr, "Failed to /sys/devices/system/cpu/cpu%d/idle_spurr\n",
cpu_sysfs_fds[i].cpu);
- goto error;
+ goto check_cpu_hotplug;
}
value = strtoll(line, NULL, 16);
@@ -216,9 +219,11 @@ int parse_sysfs_values(void)
return 0;
-error:
- close_cpu_sysfs_fds(threads_in_system);
- return -1;
+check_cpu_hotplug:
+ if(!cpu_online(cpu_sysfs_fds[i].cpu))
+ return 1;
+
+ return rc;
}
static void sig_int_handler(int signal)
@@ -917,6 +922,52 @@ void get_cpu_stat(struct sysentry *se, char *buf)
sprintf(buf, "%.2f", percent);
}
+int has_cpu_topology_changed(void)
+{
+ int i, changed = 1;
+ cpu_set_t *tmp_cpuset;
+ size_t online_cpus_size = CPU_ALLOC_SIZE(threads_in_system);
+
+ if (!online_cpus) {
+ online_cpus = CPU_ALLOC(threads_in_system);
+ if (!online_cpus) {
+ fprintf(stderr, "Failed to allocate memory for cpu_set\n");
+ return -1;
+ }
+
+ CPU_ZERO_S(online_cpus_size, online_cpus);
+
+ for (i = 0; i < threads_in_system; i++) {
+ if (!cpu_online(i))
+ continue;
+ CPU_SET_S(i, online_cpus_size, online_cpus);
+ }
+
+ return changed;
+ }
+
+ tmp_cpuset = CPU_ALLOC(threads_in_system);
+ if (!tmp_cpuset) {
+ fprintf(stderr, "Failed to allocate memory for cpu_set\n");
+ return -1;
+ }
+
+ CPU_ZERO_S(online_cpus_size, tmp_cpuset);
+
+ for (i = 0; i < threads_in_system; i++) {
+ if (!cpu_online(i))
+ continue;
+ CPU_SET_S(i, online_cpus_size, tmp_cpuset);
+ }
+
+ changed = CPU_EQUAL_S(online_cpus_size, online_cpus, tmp_cpuset);
+
+ CPU_FREE(online_cpus);
+ online_cpus = tmp_cpuset;
+
+ return changed;
+}
+
void init_sysinfo(void)
{
int rc = 0;
@@ -964,10 +1015,23 @@ void init_sysdata(void)
if (!o_scaled)
return;
+ rc = has_cpu_topology_changed();
+ if (!rc)
+ goto cpu_hotplug_restart;
+
rc = parse_sysfs_values();
- if (rc)
+ if (rc == -1)
exit(rc);
+ else if (rc)
+ goto cpu_hotplug_restart;
+
get_effective_frequency();
+
+ return;
+
+cpu_hotplug_restart:
+ close_cpu_sysfs_fds(threads_in_system);
+ init_sysinfo();
}
void update_sysdata(void)
--
2.25.3