diff options
| -rw-r--r-- | Documentation/virt/guest-halt-polling.rst (renamed from Documentation/virtual/guest-halt-polling.txt) | 12 | ||||
| -rw-r--r-- | Documentation/virt/index.rst | 1 |
2 files changed, 10 insertions, 3 deletions
diff --git a/Documentation/virtual/guest-halt-polling.txt b/Documentation/virt/guest-halt-polling.rst index b3a2a294532d..b4e747942417 100644 --- a/Documentation/virtual/guest-halt-polling.txt +++ b/Documentation/virt/guest-halt-polling.rst @@ -1,9 +1,11 @@ +================== Guest halt polling ================== The cpuidle_haltpoll driver, with the haltpoll governor, allows the guest vcpus to poll for a specified amount of time before halting. + This provides the following benefits to host side polling: 1) The POLL flag is set while polling is performed, which allows @@ -29,18 +31,21 @@ Module Parameters The haltpoll governor has 5 tunable module parameters: 1) guest_halt_poll_ns: + Maximum amount of time, in nanoseconds, that polling is performed before halting. Default: 200000 2) guest_halt_poll_shrink: + Division factor used to shrink per-cpu guest_halt_poll_ns when wakeup event occurs after the global guest_halt_poll_ns. Default: 2 3) guest_halt_poll_grow: + Multiplication factor used to grow per-cpu guest_halt_poll_ns when event occurs after per-cpu guest_halt_poll_ns but before global guest_halt_poll_ns. @@ -48,6 +53,7 @@ but before global guest_halt_poll_ns. Default: 2 4) guest_halt_poll_grow_start: + The per-cpu guest_halt_poll_ns eventually reaches zero in case of an idle system. This value sets the initial per-cpu guest_halt_poll_ns when growing. This can @@ -66,7 +72,7 @@ high once achieves global guest_halt_poll_ns value). Default: Y -The module parameters can be set from the debugfs files in: +The module parameters can be set from the debugfs files in:: /sys/module/haltpoll/parameters/ @@ -74,5 +80,5 @@ Further Notes ============= - Care should be taken when setting the guest_halt_poll_ns parameter as a -large value has the potential to drive the cpu usage to 100% on a machine which -would be almost entirely idle otherwise. + large value has the potential to drive the cpu usage to 100% on a machine + which would be almost entirely idle otherwise. diff --git a/Documentation/virt/index.rst b/Documentation/virt/index.rst index 0a8f7fda64ad..de1ab81df958 100644 --- a/Documentation/virt/index.rst +++ b/Documentation/virt/index.rst @@ -10,6 +10,7 @@ Linux Virtualization Support kvm/index uml/user_mode_linux paravirt_ops + guest-halt-polling .. only:: html and subproject |