[libvirt] [PATCH] virsh: update man page for cpu_shares parameter
The man page suggest that the cpu_shares parameter of schedinfo allows values 0-262144, but the kernel remaps values 0 and 1 to the minimum 2, just document that behaviour: [root@test ~]# cat /cgroup/cpu/libvirt/qemu/cpu.shares 1024 [root@test ~]# echo 0 > /cgroup/cpu/libvirt/qemu/cpu.shares [root@test ~]# cat /cgroup/cpu/libvirt/qemu/cpu.shares 2 [root@test ~]# echo 1 > /cgroup/cpu/libvirt/qemu/cpu.shares [root@test ~]# cat /cgroup/cpu/libvirt/qemu/cpu.shares 2 [root@test ~]# * tools/virsh.pod: update description of the cpu_shares parameter to indicate the values 0 and 1 are automatically changed by the kernel to minimal value 2 diff --git a/tools/virsh.pod b/tools/virsh.pod index a01d723..6e3febb 100644 --- a/tools/virsh.pod +++ b/tools/virsh.pod @@ -914,7 +914,9 @@ If I<--current> is specified, affect the current guest state. B<Note>: The cpu_shares parameter has a valid value range of 0-262144; Negative values are wrapped to positive, and larger values are capped at the maximum. -Therefore, -1 is a useful shorthand for 262144. +Therefore, -1 is a useful shorthand for 262144. The values 0 and 1 seems to +also be automatically changed by the Linux kernel to 2 which consider this +the minimal value. B<Note>: The weight and cap parameters are defined only for the XEN_CREDIT scheduler and are now I<DEPRECATED>. -- Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/ daniel@veillard.com | Rpmfind RPM search engine http://rpmfind.net/ http://veillard.com/ | virtualization library http://libvirt.org/
On 09/27/2011 09:06 PM, Daniel Veillard wrote:
The man page suggest that the cpu_shares parameter of schedinfo allows values 0-262144, but the kernel remaps values 0 and 1 to the minimum 2, just document that behaviour:
[root@test ~]# cat /cgroup/cpu/libvirt/qemu/cpu.shares 1024 [root@test ~]# echo 0> /cgroup/cpu/libvirt/qemu/cpu.shares [root@test ~]# cat /cgroup/cpu/libvirt/qemu/cpu.shares 2 [root@test ~]# echo 1> /cgroup/cpu/libvirt/qemu/cpu.shares [root@test ~]# cat /cgroup/cpu/libvirt/qemu/cpu.shares 2 [root@test ~]#
* tools/virsh.pod: update description of the cpu_shares parameter to indicate the values 0 and 1 are automatically changed by the kernel to minimal value 2
diff --git a/tools/virsh.pod b/tools/virsh.pod index a01d723..6e3febb 100644 --- a/tools/virsh.pod +++ b/tools/virsh.pod @@ -914,7 +914,9 @@ If I<--current> is specified, affect the current guest state.
B<Note>: The cpu_shares parameter has a valid value range of 0-262144; Negative values are wrapped to positive, and larger values are capped at the maximum. -Therefore, -1 is a useful shorthand for 262144. +Therefore, -1 is a useful shorthand for 262144. The values 0 and 1 seems to +also be automatically changed by the Linux kernel to 2 which consider this +the minimal value.
Awkward reading to a native English speaker. How about: On the Linux kernel, the values 0 and 1 are automatically converted to a minimal value of 2. ACK with that tweak. -- Eric Blake eblake@redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org
On Wed, Sep 28, 2011 at 10:54:52AM -0600, Eric Blake wrote:
On 09/27/2011 09:06 PM, Daniel Veillard wrote:
The man page suggest that the cpu_shares parameter of schedinfo allows values 0-262144, but the kernel remaps values 0 and 1 to the minimum 2, just document that behaviour:
[root@test ~]# cat /cgroup/cpu/libvirt/qemu/cpu.shares 1024 [root@test ~]# echo 0> /cgroup/cpu/libvirt/qemu/cpu.shares [root@test ~]# cat /cgroup/cpu/libvirt/qemu/cpu.shares 2 [root@test ~]# echo 1> /cgroup/cpu/libvirt/qemu/cpu.shares [root@test ~]# cat /cgroup/cpu/libvirt/qemu/cpu.shares 2 [root@test ~]#
* tools/virsh.pod: update description of the cpu_shares parameter to indicate the values 0 and 1 are automatically changed by the kernel to minimal value 2
diff --git a/tools/virsh.pod b/tools/virsh.pod index a01d723..6e3febb 100644 --- a/tools/virsh.pod +++ b/tools/virsh.pod @@ -914,7 +914,9 @@ If I<--current> is specified, affect the current guest state.
B<Note>: The cpu_shares parameter has a valid value range of 0-262144; Negative values are wrapped to positive, and larger values are capped at the maximum. -Therefore, -1 is a useful shorthand for 262144. +Therefore, -1 is a useful shorthand for 262144. The values 0 and 1 seems to +also be automatically changed by the Linux kernel to 2 which consider this +the minimal value.
Awkward reading to a native English speaker. How about:
On the Linux kernel, the values 0 and 1 are automatically converted to a minimal value of 2.
Ah, yes that's way better even for me :-), I guess I rewrote that sentence a bit too many times !
ACK with that tweak.
okay, will push, thanks ! Daniel -- Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/ daniel@veillard.com | Rpmfind RPM search engine http://rpmfind.net/ http://veillard.com/ | virtualization library http://libvirt.org/
participants (2)
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Daniel Veillard -
Eric Blake