diff options
| -rw-r--r-- | share/man/man4/smp.4 | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/share/man/man4/smp.4 b/share/man/man4/smp.4 index 4a08799..1913a1f 100644 --- a/share/man/man4/smp.4 +++ b/share/man/man4/smp.4 @@ -31,20 +31,20 @@ .Nd description of the FreeBSD Symmetric MultiProcessor kernel .Sh SYNOPSIS .Cd options SMP -.Cd options APIC_IO .Sh DESCRIPTION The .Nm kernel implements symmetric multiprocessor support. .Sh COMPATIBILITY -Support for multi-processor systems is present for all supported +Support for multi-processor systems is present for all Tier-1 architectures on .Fx . Currently, this includes alpha, i386, ia64, and sparc64. Support is enabled using .Cd options SMP . -On some, but not all platforms, it is permissible to use the 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 For i386 systems, the .Nm @@ -57,6 +57,15 @@ i386 also requires 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 +.Va machdep.hlt_logical_cpus +sysctl by setting its value to zero. .Sh SEE ALSO .Xr mptable 1 , .Xr condvar 9 , @@ -81,5 +90,8 @@ The SMPng Project relied heavily on the support of BSDi, who provided reference source code from the fine-grained SMP implementation found in .Bsx . +.Pp +.Fx 5.0 +also introduced support for SMP on the alpha, ia64, and sparc64 architectures. .Sh AUTHORS .An Steve Passe Aq fsmp@FreeBSD.org |
