CODEWITHSUNDEEP
linuxlinux-kernelclock
Manohar
Manohar

Reputation: 3975

clock source in Linux

In a system running kernel version 2.6.38 I see this sysfs file which shows the current clock source (happens to be tsc) /sys/devices/system/clocksource/clocksource0/current_clocksource

But looks like this sysfs file was introduced recently. In 2.6.9 I don't see this file. In versions that doesn't have this sysfs is there an easy to see the clock source ? When I compare the clock_gettime() ouptputs in these versions 2.6.9 seems to be at microseconds granularity and 2.6.38 is at nanoseconds granularity. Hence wondering what the clock source in 2.6.9 is..

Upvotes: 4

Views: 6323

Answers (1)

janneb
janneb

Reputation: 37208

You could try grepping clocksource and TSC from dmesg output.

FWIW, the high-resolution timers (which enabled nanosecond resolution, among many other things) were introduced in the 2.6.21 kernel or thereabouts; older kernels don't have that, as you have found out.

Upvotes: 3

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