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authorjhb <jhb@FreeBSD.org>2004-03-24 17:51:54 +0000
committerjhb <jhb@FreeBSD.org>2004-03-24 17:51:54 +0000
commit3770c58daa83631263248783fbf046b3d00746b1 (patch)
treec5cdaad04b6fd16ab476906c8addc3096a7964cb /share/man/man4/smp.4
parent53ff6f54e2971776a46586e7efe79839fdedf3d1 (diff)
downloadFreeBSD-src-3770c58daa83631263248783fbf046b3d00746b1.zip
FreeBSD-src-3770c58daa83631263248783fbf046b3d00746b1.tar.gz
- Update for the new interrupt code on i386 meaning that SMP kernels can
now run on UP machines, options APIC_IO is now spelled device apic, and HT CPUs are now enabled by default. - Add a 'I386 NOTES' section header to the i386-specific paragraphs. Someone with more mdoc fu can suggest a better name if needed. Requested by: kris (1)
Diffstat (limited to 'share/man/man4/smp.4')
-rw-r--r--share/man/man4/smp.417
1 files changed, 7 insertions, 10 deletions
diff --git a/share/man/man4/smp.4 b/share/man/man4/smp.4
index 7877fd3..c15ccdb 100644
--- a/share/man/man4/smp.4
+++ b/share/man/man4/smp.4
@@ -42,10 +42,9 @@ architectures on
Currently, this includes alpha, i386, ia64, and sparc64.
Support is enabled using
.Cd options SMP .
-On most platforms it is permissible to use the SMP
-kernel configuration on non-SMP equipped motherboards.
-The only exception to this rule is the i386 platform.
-.Pp
+It is permissible to use the SMP kernel configuration on non-SMP equipped
+motherboards.
+.Sh I386 NOTES
For i386 systems, the
.Nm
kernel supports motherboards that follow the Intel MP specification,
@@ -53,19 +52,17 @@ version 1.4.
In addition to
.Cd options SMP ,
i386 also requires
-.Cd options APIC_IO .
+.Cd device apic .
The
.Xr mptable 1
command may be used to view the status of multi-processor support.
.Pp
.Fx
supports hyperthreading on Intel CPU's on the i386 platform.
-By default, logical CPUs are not used to execute user processes due to
-performance penalties under common loads.
-To allow the logical CPUs to execute user processes,
-turn off the
+Since using logical CPUs can cause performance penalties under certain loads,
+the logical CPUs can be disabled by setting the
.Va machdep.hlt_logical_cpus
-sysctl by setting its value to zero.
+sysctl to one.
.Sh SEE ALSO
.Xr mptable 1 ,
.Xr condvar 9 ,
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