kata-containers/s390-tools
1
0
Fork 0
mirror of https://github.com/ibm-s390-linux/s390-tools.git synced 2026-08-05 02:14:52 +00:00
Code Issues Packages Projects Releases Wiki Activity

cpuplugd: Halt cpu hotplugging on vertical polarization

Browse Source 
On vertical polarization, kernel can be adjusting CPU capacities
dynamically, and cpuplugd can interfere this with hotplug operations
causing performance degradation. To prevent this, check if system has
switched its polarization state, and act accordingly.
If system is on vertical polarization when daemon starts, no CPU hotplug
action is triggered. If system changes to vertical polarization during
daemon runtime, revert cpuhotplug adjustments and stop further CPU
hotplug actions. If system switches back to horizontal polarization
during runtime of the daemon, start evaluating CPU hotplug rules and
trigger adjustments.

Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
This commit is contained in:
Mete Durlu
2024-05-23 13:58:08 +02:00
committed by Jan Höppner
parent c91d172c99
commit 147ff1bf49
6 changed files with 111 additions and 46 deletions
Download Patch File Download Diff File Expand all files Collapse all files

92
cpuplugd/config.c
View File

@@ -204,6 +204,45 @@ void parse_configfile(char *file)
fclose(filp);
}
void apply_cpu_config(void)
{
/*
* Check that the initial number of cpus is not below the
* minimum
*/
if (num_cpu_start < cfg.cpu_min &&
get_numcpus() >= cfg.cpu_min) {
cpuplugd_debug("The number of online cpus is below ");
cpuplugd_debug("the minimum and will be increased.\n");
while (get_num_online_cpus() < cfg.cpu_min) {
if (hotplug_one_cpu())
break;
}
}
if (get_num_online_cpus() > cfg.cpu_max) {
cpuplugd_debug("The number of online cpus is above the maximum");
cpuplugd_debug(" and will be decreased.\n");
while (get_num_online_cpus() > cfg.cpu_max) {
if (hotunplug_one_cpu())
break;
}
}
if (cfg.cpu_min > get_numcpus()) {
/*
* This check only works if nobody used the
* additional_cpus in the boot parameter section
*/
cpuplugd_debug("The minimum amount of cpus is above the ");
cpuplugd_debug("number of available cpus.\n");
cpuplugd_exit("Detected %d available cpus\n", get_numcpus());
}
if (get_num_online_cpus() < cfg.cpu_min) {
cpuplugd_debug("Failed to set the number of online cpus to ");
cpuplugd_debug("the minimum. ");
cpuplugd_exit("Aborting.\n");
}
}
/*
* Check if the required settings are found in the configuration file.
* "Autodetect" if cpu and/or memory hotplug configuration entries
@@ -261,44 +300,23 @@ void check_config()
/*
* Save the number of online cpus and the cmm_pagesize at startup,
* so that we can enable exactly the same amount when the daemon ends
*
* Don't adjust cpus if system is on vertical polarization
*/
if (cpu) {
num_cpu_start = get_num_online_cpus();
cpuplugd_debug("Daemon started with %d active cpus.\n",
num_cpu_start);
/*
* Check that the initial number of cpus is not below the
* minimum
*/
if (num_cpu_start < cfg.cpu_min &&
get_numcpus() >= cfg.cpu_min) {
cpuplugd_debug("The number of online cpus is below "
"the minimum and will be increased.\n");
while (get_num_online_cpus() < cfg.cpu_min) {
if (hotplug_one_cpu())
break;
}
}
if (get_num_online_cpus() > cfg.cpu_max) {
cpuplugd_debug("The number of online cpus is above the maximum"
" and will be decreased.\n");
while (get_num_online_cpus() > cfg.cpu_max) {
if (hotunplug_one_cpu())
break;
}
}
if (cfg.cpu_min > get_numcpus())
/*
* This check only works if nobody used the
* additional_cpus in the boot parameter section
*/
cpuplugd_exit("The minimum amount of cpus is above "
"the number of available cpus.\n"
"Detected %d available cpus\n",
get_numcpus());
if (get_num_online_cpus() < cfg.cpu_min)
cpuplugd_exit("Failed to set the number of online "
"cpus to the minimum. Aborting.\n");
saved_polarization = get_polarization();
num_cpu_start = get_num_online_cpus();
cpuplugd_debug("Daemon started with %d active cpus.\n",
num_cpu_start);
if (saved_polarization < 0) {
cpuplugd_debug("Daemon couldn't determine system polarization\n");
cpuplugd_debug("Starting without evaluating cpu rules\n");
} else if (saved_polarization == PLR_VERTICAL) {
cpuplugd_debug("Daemon started with vertical polarization.\n");
cpuplugd_debug("Cpu adjustments won't be made until system ");
cpuplugd_debug("is in horizontal polarization\n");
} else if (saved_polarization == PLR_HORIZONTAL &&
cpu == 1) {
apply_cpu_config();
}
if (memory == 1) {
/*