Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6

[karo-tx-linux.git] / Documentation / trace / ftrace.txt

diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index 185c39fea2a022b6c6a7910e07a925d9688f542f..5596e2d71d6d836677fd98905ce0f7272b9c78c0 100644 (file)
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -362,6 +362,26 @@ of ftrace. Here is a list of some of the key files:
                  to correlate events across hypervisor/guest if
                  tb_offset is known.
 
+         mono: This uses the fast monotonic clock (CLOCK_MONOTONIC)
+               which is monotonic and is subject to NTP rate adjustments.
+
+         mono_raw:
+               This is the raw monotonic clock (CLOCK_MONOTONIC_RAW)
+               which is montonic but is not subject to any rate adjustments
+               and ticks at the same rate as the hardware clocksource.
+
+         boot: This is the boot clock (CLOCK_BOOTTIME) and is based on the
+               fast monotonic clock, but also accounts for time spent in
+               suspend. Since the clock access is designed for use in
+               tracing in the suspend path, some side effects are possible
+               if clock is accessed after the suspend time is accounted before
+               the fast mono clock is updated. In this case, the clock update
+               appears to happen slightly sooner than it normally would have.
+               Also on 32-bit systems, it's possible that the 64-bit boot offset
+               sees a partial update. These effects are rare and post
+               processing should be able to handle them. See comments in the
+               ktime_get_boot_fast_ns() function for more information.
+
        To set a clock, simply echo the clock name into this file.
 
          echo global > trace_clock