From: Mathieu Desnoyers Date: Thu, 28 Jul 2011 15:05:06 +0000 (-0400) Subject: Update readme: discuss perf counters X-Git-Tag: v2.0-pre3~1 X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=a3a8ea221c9674f6a30b75aee373c95c0556d769;p=lttng-modules.git Update readme: discuss perf counters Signed-off-by: Mathieu Desnoyers --- diff --git a/README b/README index 583d0e02..1a7cea16 100644 --- a/README +++ b/README @@ -46,3 +46,10 @@ Support for LTTng 0.x clocks will be added back soon into LTTng 2.0. Please note that lttng-modules 2.0 can build on a Linux kernel patched with the LTTng 0.x patchset, but the lttng-modules 2.0 replace the lttng-modules 0.x, so both tracers cannot be installed at the same time for a given kernel version. + +* Note about Perf PMU counters support + +Each PMU counter has its zero value set when it is attached to a context with +add-context. Therefore, it is normal that the same counters attached to both the +stream context and event context show different values for a given event; what +matters is that they increment at the same rate.