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doc: spelling and grammar improvements

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Signed-off-by: David B. Kinder <david.b.kinder@intel.com>
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David B. Kinder
2020-10-01 17:45:47 -07:00
committed by David Kinder
parent f300d1ff77
commit 576a3b5947
30 changed files with 244 additions and 241 deletions
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12
doc/tutorials/rtvm_performance_tips.rst
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@@ -59,7 +59,7 @@ Avoid VM-exit latency
*********************
VM-exit has a significant negative impact on virtualization performance.
A single VM-exit causes a several micro-second or longer latency,
A single VM-exit causes several micro-seconds or longer latency,
depending on what's done in VMX-root mode. VM-exit is classified into two
types: triggered by external CPU events or triggered by operations initiated
by the vCPU.
@@ -90,7 +90,7 @@ Tip: Do not use CPUID in a real-time critical section.
subsequent instructions after the RDTSCP normally have data dependency
on it, so they must wait until the RDTSCP has been executed.
RDMSR or WRMSR are instructions that cause VM-exits conditionally. On the
RDMSR and WRMSR are instructions that cause VM-exits conditionally. On the
ACRN RTVM, most MSRs are not intercepted by the HV, so they won't cause a
VM-exit. But there are exceptions for security consideration:
@@ -114,7 +114,7 @@ Tip: Utilize Preempt-RT Linux mechanisms to reduce the access of ICR from the RT
#. Add ``domain`` to ``isolcpus`` ( ``isolcpus=nohz,domain,1`` ) to the kernel parameters.
#. Add ``idle=poll`` to the kernel parameters.
#. Add ``rcu_nocb_poll`` along with ``rcu_nocbs=1`` to the kernel parameters.
#. Disable the logging service like journald, syslogd if possible.
#. Disable the logging service isuch as ``journald`` or ``syslogd`` if possible.
The parameters shown above are recommended for the guest Preempt-RT
Linux. For an UP RTVM, ICR interception is not a problem. But for an SMP
@@ -173,9 +173,9 @@ Tip: Disable timer migration on Preempt-RT Linux.
Tip: Add ``mce=off`` to RT VM kernel parameters.
This parameter disables the mce periodic timer and avoids a VM-exit.
Tip: Disable the Intel processor C-State and P-State of the RTVM.
Tip: Disable the Intel processor C-state and P-state of the RTVM.
Power management of a processor could save power, but it could also impact
the RT performance because the power state is changing. C-State and P-State
the RT performance because the power state is changing. C-state and P-state
PM mechanism can be disabled by adding ``processor.max_cstate=0
intel_idle.max_cstate=0 intel_pstate=disable`` to the kernel parameters.
@@ -193,4 +193,4 @@ Tip: Disable the software workaround for Machine Check Error on Page Size Change
:option:`CONFIG_MCE_ON_PSC_WORKAROUND_DISABLED` option could be set for performance.
.. note::
The tips for preempt-RT Linux are mostly applicable to the Linux-based RT OS as well, such as Xenomai.
The tips for preempt-RT Linux are mostly applicable to the Linux-based RTOS as well, such as Xenomai.