10 More Discussions You Might Find Interesting
1. UNIX for Beginners Questions & Answers
I read that Entitlement CPU should be set to max 75% compare to Virtual CPU. May I know the reason.
I have set the Entitlement CPU = Virtual CPU on AIX . It works fine .
Can you help to understand. (1 Reply)
Discussion started by: gabhanes
1 Replies
2. Linux
Hey all,
So, I want to build a tablet that will run a standard 32-bit version of Linux.
The reason for this is I need to run my application on a very bright screen to use outdoors. I don't want to spend the time porting all of the code to use on an ARM tablet. The application works flawlessly... (2 Replies)
Discussion started by: fedora18
2 Replies
3. UNIX for Dummies Questions & Answers
We have a single threaded application which is restricted by CPU usage even though there are multiple CPUs on the server, hence leading to significant performance issues. Is it possible to merge / combine multiple CPUs at OS level so it appear as a single CPU for the application? (6 Replies)
Discussion started by: Dissa
6 Replies
4. Hardware
Hi, I am experiencing troubles with dual monitors in fedora 16. During boot time both monitors are working, but when system starts one monitor automatically shut down. It happend out of the blue. Some time before when I updated system this happend but then I booted older kernel release and... (0 Replies)
Discussion started by: wakatana
0 Replies
5. UNIX Benchmarks
p520's prtconf ..two internal drives 10K RPMs 140G, 2 dual core 1.5 GHz processors, 8 Gig of RAM, running AIX 7.1, with the newest gcc compiler
The numbers don't make sense,
Can someone comment ??
BYTE UNIX Benchmarks (Version 3.11)
System -- AIX p520 1 7 00CD5D0C4C00
Start... (2 Replies)
Discussion started by: ppchu99
2 Replies
6. Hardware
For the selection of motherboards, is there any naming convention in the type numbers? There is usually a brand name and sometimes a version name, but more essential details like form factor, SATA speed and maximum amount of RAM is never given. Is there a reason for that? Is there any background... (2 Replies)
Discussion started by: figaro
2 Replies
7. Solaris
Can anyone tell me difference between cpu-shares vs cpu-cap in solaris & how FSS will work with cpu-caps ? (9 Replies)
Discussion started by: fugitive
9 Replies
8. Solaris
Hello Friends,
On one of my Solaris 10 box, CPU usage shows 100% using "sar", "vmstat". However, it has 4 CPUs and prstat and glance are not showing enough processes to justify high CPU utilization.
=========================================================================
$ prstat -a
... (4 Replies)
Discussion started by: mahive
4 Replies
9. UNIX for Dummies Questions & Answers
hi,
i want to know cpu utilizatiion per process per cpu..for single processor also if multicore in linux ..to use these values in shell script to kill processes exceeding cpu utilization.ps (pcpu) command does not give exact values..top does not give persistant values..psstat,vmstat..does njot... (3 Replies)
Discussion started by: pankajd
3 Replies
10. UNIX for Dummies Questions & Answers
Hi have just built a new sunfire 280r with solaris 9 and i Have 2 questions
1) where can i view some information that will tell me for definate that the 2*900 mhz processors are both being used, i tried using "top" but it doesnt tell me for sure that both processors are churning away together
... (3 Replies)
Discussion started by: hcclnoodles
3 Replies
SMP(4) BSD Kernel Interfaces Manual SMP(4)
NAME
SMP -- description of the FreeBSD Symmetric Multi-Processor kernel
SYNOPSIS
options SMP
DESCRIPTION
The SMP kernel implements symmetric multi-processor support.
COMPATIBILITY
Support for multi-processor systems is present for all Tier-1 architectures on FreeBSD. Currently, this includes amd64, i386, ia64, and
sparc64. Support is enabled using options SMP. It is permissible to use the SMP kernel configuration on non-SMP equipped motherboards.
I386 NOTES
For i386 systems, the SMP kernel supports motherboards that follow the Intel MP specification, version 1.4. In addition to options SMP, i386
also requires device apic. The mptable(1) command may be used to view the status of multi-processor support.
The number of CPUs detected by the system is available in the read-only sysctl variable hw.ncpu.
FreeBSD allows specific CPUs on a multi-processor system to be disabled. The sysctl variable machdep.hlt_cpus is an integer bitmask denoting
CPUs to halt, counting from 0. Setting a bit to 1 will result in the corresponding CPU being disabled.
The sched_ule(4) scheduler implements CPU topology detection and adjusts the scheduling algorithms to make better use of modern multi-core
CPUs. The sysctl variable kern.sched.topology_spec reflects the detected CPU hardware in a parsable XML format. The top level XML tag is
<groups>, which encloses one or more <group> tags containing data about individual CPU groups. A CPU group contains CPUs that are detected
to be "close" together, usually by being cores in a single multi-core processor. Attributes available in a <group> tag are "level", corre-
sponding to the nesting level of the CPU group and "cache-level", corresponding to the level of CPU caches shared by the CPUs in the group.
The <group> tag contains the <cpu> and <flags> tags. The <cpu> tag describes CPUs in the group. Its attributes are "count", corresponding
to the number of CPUs in the group and "mask", corresponding to the integer binary mask in which each bit position set to 1 signifies a CPU
belonging to the group. The contents (CDATA) of the <cpu> tag is the comma-delimited list of CPU indexes (derived from the "mask"
attribute). The <flags> tag contains special tags (if any) describing the relation of the CPUs in the group. The possible flags are cur-
rently "HTT" and "SMT", corresponding to the various implementations of hardware multithreading. An example topology_spec output for a sys-
tem consisting of two quad-core processors is:
<groups>
<group level="1" cache-level="0">
<cpu count="8" mask="0xff">0, 1, 2, 3, 4, 5, 6, 7</cpu>
<flags></flags>
<children>
<group level="2" cache-level="0">
<cpu count="4" mask="0xf">0, 1, 2, 3</cpu>
<flags></flags>
</group>
<group level="2" cache-level="0">
<cpu count="4" mask="0xf0">4, 5, 6, 7</cpu>
<flags></flags>
</group>
</children>
</group>
</groups>
This information is used internally by the kernel to schedule related tasks on CPUs that are closely grouped together.
FreeBSD supports hyperthreading on Intel CPU's on the i386 and AMD64 platforms. Since using logical CPUs can cause performance penalties
under certain loads, the logical CPUs can be disabled by setting the machdep.hlt_logical_cpus sysctl to one. Note that this operation is
different from the mechanism used by the cpuset(1).
SEE ALSO
mptable(1), sysctl(8), condvar(9), msleep(9), mtx_pool(9), mutex(9), sema(9), sx(9), rwlock(9), sched_4bsd(4), sched_ule(4), cpuset(1)
HISTORY
The SMP kernel's early history is not (properly) recorded. It was developed in a separate CVS branch until April 26, 1997, at which point it
was merged into 3.0-current. By this date 3.0-current had already been merged with Lite2 kernel code.
FreeBSD 5.0 introduced support for a host of new synchronization primitives, and a move towards fine-grained kernel locking rather than
reliance on a Giant kernel lock. The SMPng Project relied heavily on the support of BSDi, who provided reference source code from the fine-
grained SMP implementation found in BSD/OS.
FreeBSD 5.0 also introduced support for SMP on the ia64 and sparc64 architectures.
AUTHORS
Steve Passe <fsmp@FreeBSD.org>
BSD
May 7, 2008 BSD