X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=README;h=1a7cea16e4ca49e72ae957e1d3723edb8d746a19;hb=57105fc258cabb75b3a579aaba53b2024fd340e0;hp=52bf44d9ee9bd4ad3f2c679742bbe1a17bc847dc;hpb=c65998d6fee4911c55eceea8d1a1c9bafbea40e8;p=lttng-modules.git

diff --git a/README b/README
index 52bf44d9..1a7cea16 100644
--- a/README
+++ b/README
@@ -37,12 +37,19 @@ http://lttng.org/lttng2.0
 Please note that the LTTng-UST 2.0 (user-space tracing counterpart of LTTng 2.0)
 is still in active development and not released yet.
 
-So far, it has been tested on vanilla Linux kernels 2.6.38, 2.6.39 and 3.0-rc7
-(on x86 32/64-bit, and powerpc 32-bit at the moment). It should work fine with
-newer kernels and other architectures, but expect build issues with kernels
-older than 2.6.36. The clock source currently used is the standard gettimeofday
-(slower, less scalable and less precise than the LTTng 0.x clocks).  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
+So far, it has been tested on vanilla Linux kernels 2.6.38, 2.6.39 and 3.0 (on
+x86 32/64-bit, and powerpc 32-bit at the moment, build tested on ARM). It should
+work fine with newer kernels and other architectures, but expect build issues
+with kernels older than 2.6.36. The clock source currently used is the standard
+gettimeofday (slower, less scalable and less precise than the LTTng 0.x clocks).
+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.