Linux kernel 2.6/CentOS 4 & 5 ‘s clock source under a virtualized environment

Under Linux kernel 2.6, the default system timer is set to 1000Hz which will consumes lot of cpu cycle under a virtualized environment even it is in idle state. To run it under a virtualized environment, suitable kernel parameters should be passed to change the clock source and time divider :

for RHEL-4 32 bits: “clock=pmtmr divider=10”
for RHEL-5 32 bits: “divider=10 clocksource=acpi_pm”
for RHEL-4 64 bits: “notsc divider=10”
for RHEL-5 64 bits: “notsc divider=10”

For more information , see this Vmware KB :

Leave a Reply

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>