Questions tagged [smp]
13 questions
9
votes
1 answer
"Remote function call interrupts" (CAL in /proc interrupts). What is it?
I'm running a test program which generates a large number of threads and asynchronous I/O. I'm seeing very high counts of these interrupts in /proc/interrupts, the program cannot scale beyond a certain point because CPUs are 100% saturated with…
twblamer
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7
votes
2 answers
VirtualBox guest: 16 CPUs detected but only 1 online
I am running VirtualBox (using the Qiime image http://qiime.org/install/virtual_box.html)
The physical hardware is a 32 core machine. The virtual machine in VirtualBox has been given 16 cores.
When booting I get:
Ubuntu 10.04.1 LTS
Linux…
Ole Tange
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7
votes
2 answers
OpenBSD SMP support
The OpenBSD 4.9 release announcement says
"SMP kernels can now boot on machines with up to 64 cores;"
So OpenBSD does support several CPU's/cores?
If i have a Core2Duo cpu in my laptop (t7100) then would it bring greater performance if I use "SMP"…
LanceBaynes
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6
votes
3 answers
Making a IRQ SMP Affinity change permanent
I have to change the smp_affinity of a interrupt permanently. The following code needs to be executed when the server reboots:
echo "1" > /proc/irq/152/smp_affinity_list
echo "2" > /proc/irq/151/smp_affinity_list
echo "3" >…
Philip
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3
votes
0 answers
How to decide how much memory to allocate per core for MPI app GENE?
This is required information for some MPI using app that I am working with...
From its Makefile template:
#insert memory per core and uncomment the following line
#PREPROC= -D'MB_PER_CORE=750'
Note that said scientific app runs also on NUMA…
Jakub Narębski
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1
vote
1 answer
How to disable CPU hotplug feature (and kernel thread) in Linux-5.10.24
I am working on an embedded Linux system, which is using kernel-5.10.24.
As the system resource is limited, so I want to minimize the CPU/memory/storage usage.
From ps -ax I found 2 kernel threads as follows,
14 root 0:00 [cpuhp/0]
15…
wangt13
- 317
- 1
- 8
1
vote
2 answers
Kernel not detecting multicore cpu
Kernel Version
3.3.4-5.fc17.x86_64
CPU info:
sashan@dhcp-au-122 ~ $ cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 42
model name : Intel(R) Core(TM) i7-2640M CPU @ 2.80GHz
stepping : 7
microcode :…
sashang
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1
vote
0 answers
Does the lack of kernel feature (XENFEAT_hvm_pirqs) cause RedHat EC2 interrupt issue?
I have a RedHat 6.5 on AWS EC2 running kernel 2.6.32.431, I have installed the ixgbevf driver with the minimum version the doc recommends. After configuration the system now has 2 queues(IRQs)：
grep eth0-TxRx /proc/interrupts
48: 7986 0 0 0 0 0 0 0…
Jepsenwan
- 45
- 6
1
vote
1 answer
Can the 0th physical core used asymmetrically on linux?
In an SMP and with a fair scheduling algorithm I'd expect all physical cores of a machine to get used evenly by linux. In theory I believe this is the case, but in practice I suspect not.
Does anyone have any good explanations why an average linux…
Andrew Parker
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1
vote
0 answers
Why I am not able to bind the interrupts with code LOC, IWI, RES when irqbalance is disabled?
On Ubuntu 14.04, I am trying to bind all the interrupts to core 0 and 1 out of 4 cores. I have disabled the irqbalance daemon via file /etc/init/irqbalance.override. Then I went to every interrupt in /proc/irq and changed the files…
rahul.deshmukhpatil
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0
votes
2 answers
Get CPU core id executing a process which suddenly exits
In Linux, in a multi-core processor, ps, top and similar tools can show the CPU logical core id running a specific process. If the process runs for a certain amount of time, it's easy to identify it in the process list.
I have instead a stand-alone…
BowPark
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0
votes
0 answers
Is this a safe way to pass data from a trace_sys_enter probe to a trace_sys_exit probe in Linux?
I am writing a kernel module that hooks into system call entry and exit code using kernel tracepoints (trace_sys_enter and trace_sys_exit).
I need to pass data from the system call entry probe to the system call exit probe. I cannot simply use a…
anroesti
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- 1
0
votes
1 answer
linux / SMP -- suspend immediately after wakeup from suspend
(Please note -- I read this post and it is not a duplicate.)
So for years, my linux laptop has allowed me to both suspend to disk and (with a little effort) suspend to RAM with one of these two commands
echo -n mem > /sys/power/state
echo "disk" >…
hymie
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