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author | jkoshy <jkoshy@FreeBSD.org> | 2004-12-18 01:13:37 +0000 |
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committer | jkoshy <jkoshy@FreeBSD.org> | 2004-12-18 01:13:37 +0000 |
commit | fc0ef2974e3e8c05a57d77ea20d8ed0553394c9f (patch) | |
tree | dce483510f5a7815e1aad45b6ac7e0c3a5618a83 /share/man/man4/smp.4 | |
parent | 1b6e938d41aa5430faf04fdfc4c99fb0b46c7b03 (diff) | |
download | FreeBSD-src-fc0ef2974e3e8c05a57d77ea20d8ed0553394c9f.zip FreeBSD-src-fc0ef2974e3e8c05a57d77ea20d8ed0553394c9f.tar.gz |
Document "machdep.hlt_cpus".
Reviewed by: ru
Diffstat (limited to 'share/man/man4/smp.4')
-rw-r--r-- | share/man/man4/smp.4 | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/share/man/man4/smp.4 b/share/man/man4/smp.4 index 28dacfc..198ac7e 100644 --- a/share/man/man4/smp.4 +++ b/share/man/man4/smp.4 @@ -23,18 +23,18 @@ .\" .\" $FreeBSD$ .\" -.Dd December 5, 2002 +.Dd December 17, 2004 .Dt SMP 4 .Os .Sh NAME .Nm SMP -.Nd description of the FreeBSD Symmetric MultiProcessor kernel +.Nd description of the FreeBSD Symmetric Multi-Processor kernel .Sh SYNOPSIS .Cd options SMP .Sh DESCRIPTION The .Nm -kernel implements symmetric multiprocessor support. +kernel implements symmetric multi-processor support. .Sh COMPATIBILITY Support for multi-processor systems is present for all Tier-1 architectures on @@ -57,6 +57,18 @@ The .Xr mptable 1 command may be used to view the status of multi-processor support. .Pp +The number of CPUs detected by the system is available in +the read-only sysctl variable +.Va hw.ncpu . +.Pp +.Fx +allows specific CPUs on a multi-processor system to be disabled. +The sysctl variable +.Va 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. +.Pp .Fx supports hyperthreading on Intel CPU's on the i386 platform. Since using logical CPUs can cause performance penalties under certain loads, @@ -65,6 +77,7 @@ the logical CPUs can be disabled by setting the sysctl to one. .Sh SEE ALSO .Xr mptable 1 , +.Xr sysctl 8 , .Xr condvar 9 , .Xr msleep 9 , .Xr mtx_pool 9 , |