I don't have cpufreq-info/set, utility,
How can I change cpu frequency manually using sysfs & CPUFREQ ?
According to this:
If you are using the userspace governor, you can write to /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed to change the current speed.
# echo 700000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed
# cat /proc/cpuinfo
cpu MHz : 697.252
# echo 900000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed
# cat /proc/cpuinfo
cpu MHz : 976.152
To enable userspace governor you must write userspace into /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor:
# echo userspace > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
Related
I want to disable the timer interrupt on some of the cores (1-2) on my machine which is a x86 running centos 7 with rt patch, both cores are isolated cores with nohz_full, (you can see the cmdline) but timer interrupt continues to interrupt the real time process which are running on core1 and core2.
1. uname -r
3.10.0-693.11.1.rt56.632.el7.x86_64
2. cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-3.10.0-693.11.1.rt56.632.el7.x86_64 \
root=/dev/mapper/centos-root ro crashkernel=auto \
rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rhgb quiet \
default_hugepagesz=2M hugepagesz=2M hugepages=1024 \
intel_iommu=on isolcpus=1-2 irqaffinity=0 intel_idle.max_cstate=0 \
processor.max_cstate=0 idle=mwait tsc=perfect rcu_nocbs=1-2 rcu_nocb_poll \
nohz_full=1-2 nmi_watchdog=0
3. cat /proc/interrupts
CPU0 CPU1 CPU2
0: 29 0 0 IO-APIC-edge timer
.....
......
NMI: 0 0 0 Non-maskable interrupts
LOC: 835205157 308723100 308384525 Local timer interrupts
SPU: 0 0 0 Spurious interrupts
PMI: 0 0 0 Performance monitoring interrupts
IWI: 0 0 0 IRQ work interrupts
RTR: 0 0 0 APIC ICR read retries
RES: 347330843 309191325 308417790 Rescheduling interrupts
CAL: 0 935 935 Function call interrupts
TLB: 320 22 58 TLB shootdowns
TRM: 0 0 0 Thermal event interrupts
THR: 0 0 0 Threshold APIC interrupts
DFR: 0 0 0 Deferred Error APIC interrupts
MCE: 0 0 0 Machine check exceptions
MCP: 2 2 2 Machine check polls
CPUs/Clocksource:
4. lscpu | grep CPU.s
CPU(s): 3
On-line CPU(s) list: 0-2
NUMA node0 CPU(s): 0-2
5. cat /sys/devices/system/clocksource/clocksource0/current_clocksource
tsc
Thanks a lot for any help.
Moses
Even with nohz_full= you get some ticks on the isolated CPUs:
Some process-handling operations still require the occasional scheduling-clock tick. These operations include calculating CPU load, maintaining sched average, computing CFS entity vruntime, computing avenrun, and carrying out load balancing. They are currently accommodated by scheduling-clock tick every second or so. On-going work will eliminate the need even for these infrequent scheduling-clock ticks.
(Documentation/timers/NO_HZ.txt, cf. (Nearly) full tickless operation in 3.10 LWN, 2013)
Thus, you have to check the rate of the local timer, e.g.:
$ perf stat -a -A -e irq_vectors:local_timer_entry sleep 120
(while your isolated threads/processes are running)
Also, nohz_full= is only effective if there is just one runnable task on each isolated core. You can check that with e.g. ps -L -e -o pid,tid,user,state,psr,cmd and cat /proc/sched_debug.
Perhaps you need to move some (kernel) tasks to you house-keeping core, e.g.:
# tuna -U -t '*' -c 0-4 -m
You can get more insights into what timers are still active by looking at /proc/timer_list.
Another method to investigate causes for possible interruption is to use the functional tracer (ftrace). See also Reducing OS jitter due to per-cpu kthreads for some examples.
I see nmi_watchdog=0 in your kernel parameters, but you don't disable the soft watchdog. Perhaps this is another timer tick source that would show up with ftrace.
You can disable all watchdogs with nowatchdog.
Btw, some of your kernel parameters seem to be off:
tsc=perfect - do you mean tsc=reliable? The 'perfect' value isn't documented in the kernel docs
idle=mwait - do you mean idle=poll? Again, I can't find the 'mwait' value in the kernel docs
intel_iommu=on - what's the purpose of this?
On Linux I can get UUID are stored in some files on system (in example /var/lib/dbus/machine-id, /proc/sys/kernel/random/uuid, /proc/sys/kernel/random/boot_id), can I find similar files on OS X?
You can use uuidgen:
/usr/bin/uuidgen
$ uuidgen
6A786B80-8D52-4344-93D1-37C95F6C803A
Your question seems somewhat confused...
If you want to generate a unique UUID for some reason, use #ergonaut's answer:
uuidgen
70095BA9-B866-42F2-9DE4-606F54EBBA88
If you want to get a unique identifier for a particular CPU/machine, you can use the system_profiler like this:
system_profiler SPHardwareDataType
Output
Hardware:
Hardware Overview:
Model Name: iMac
Model Identifier: iMac12,2
Processor Name: Intel Core i7
Processor Speed: 3.4 GHz
Number of Processors: 1
Total Number of Cores: 4
L2 Cache (per Core): 256 KB
L3 Cache: 8 MB
Memory: 16 GB
Boot ROM Version: IM121.0047.B21
SMC Version (system): 1.72f2
Serial Number (system): DGKH80PXDHJW
Hardware UUID: 1025AC04-9F9E-5342-9EF4-206EBAE40BF6
Or, if you want to select one of those values specifically, you can use:
system_profiler SPHardwareDataType | awk '/UUID/ { print $3; }'
1025AC04-9F9E-5342-9EF4-206EBAE40BF6
Or, you can use the MAC address of your primary Ethernet interface like this:
ifconfig en0 | awk '/ether/{print $2}'
3c:07:54:76:38:cd
I want to find the CPU process usage for all Oracle processes on an AIX box.
On Solaris I can do the following:
prstat -n 400 -c -s cpu -p 9013 1 1
PID USERNAME SIZE RSS STATE PRI NICE TIME CPU PROCESS/NLWP
9013 oracle 3463M 2928M sleep 53 0 0:00:35 0.9% oracle/2
Total: 1 processes, 2 lwps, load averages: 2.25, 2.32, 2.40
This basically reports the CPU usage for a given process ID (in this case 9013). Given a list of all Oracle PID’s I can use this command to get the CPU usage for each one, sum them up and hey presto I have my Oracle database CPU usage.
How can I get the same with AIX?
Thanks
You can try nmon or topas, which will show the current %CPU. You might also want to look into using WLM to create a class for all the Oracle processes, then use wlmstat to see the CPU usage for that class. That would save you the trouble of adding them up manually.
I know that using Activity Monitor we can see CPU utilisation.But i want to get this information of my remote system through script. top command is not helpful for me. Please comment me any other way to get it.
What is the objection to top in logging mode?
top -l 1 | grep -E "^CPU|^Phys"
CPU usage: 3.27% user, 14.75% sys, 81.96% idle
PhysMem: 5807M used (1458M wired), 10G unused.
Or use sysctl
sysctl vm.loadavg
vm.loadavg: { 1.31 1.85 2.00 }
Or use vm_stat
vm_stat
Mach Virtual Memory Statistics: (page size of 4096 bytes)
Pages free: 3569.
Pages active: 832177.
Pages inactive: 283212.
Pages speculative: 2699727.
Pages throttled: 0.
Pages wired down: 372883.
I've set IRQ affinity in the past on Linux by setting values to the proc files. [1]
However, I noticed that when I do this on an system that uses MSI-X for the device
(PCIe) that I want to set affinity for e.g. NIC, the /proc/interrupt counters increment
for each core for the IRQ and not for the single core I set it for. Where in a non-
MSI-X system the specified core answers the interrupts.
I'm using Linux kernel 3.11.
Short: Can IRQ affinity be set for devices that use MSI-X interrupts?
[1] https://www.kernel.org/doc/Documentation/IRQ-affinity.txt
Unburrying this thread, I am trying to set IRQ (MSI-X) cpu affinity for my SATA controller in order to avoid cpu switching delays.
So far, I got the current used IRQ via:
IRQ=$(cat /proc/interrupts | grep ahci | awk -F':' '/ /{gsub(/ /, "", $1); print $1}')
Just looking at the interrupts via cat /proc/interrupts shows that multiple CPUs are involved in my sata controller handling.
I then set the IRQ affinity (cpu 2 in my case) via
echo 02 > /proc/irq/$IRQ/smp_affinity
I can test the effective affinity with
cat /proc/irq/$IRQ/effective_affinity
After a while of disk benchmarking, I noticed that the affinity stays as configured.
Example:
Before benchmark, having bound IRQ 134 to cpu 2:
cat /proc/interrupts | egrep "ahci|CPU"
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
134: 12421581 1 0 17 4166 0 0 0 IR-PCI-MSI 376832-edge ahci[0000:00:17.0]
After benchmark:
cat /proc/interrupts | egrep "ahci|CPU"
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
134: 12421581 2724836 0 17 4166 0 0 0 IR-PCI-MSI 376832-edge ahci[0000:00:17.0]
So in my case, the affinity that I've setup stayed as it should.
I can only imagine that you have irqbalance running as a service.
Have you checked that ?
In my case, running irqbalance redistributes the affinity and overrides the one I setup.
My test system: CentOS 8.2 4.18.0-193.6.3.el8_2.x86_64 #1 SMP Wed Jun 10 11:09:32 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
In the end, I did not achieve better disk utilization / performance. My initial problem is that fio benchmarks do not use 100% disk, mere some values between 75-85% (and sometimes 97%, without me knowing why).