X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=README;h=1a7cea16e4ca49e72ae957e1d3723edb8d746a19;hb=a3a8ea221c9674f6a30b75aee373c95c0556d769;hp=fb0561df4f798741820f099053b30ce2847ef0c0;hpb=fe17837951dce26cb69450161716d7a621380441;p=lttng-modules.git

diff --git a/README b/README
index fb0561df..1a7cea16 100644
--- a/README
+++ b/README
@@ -20,27 +20,36 @@ need for additional patches. Other features:
 To build and install, you will need to have your kernel headers available (or
 access to your full kernel source tree), and use:
 
-make
-make modules_install
+% make
+# make modules_install
 
 If you need to specify the target directory to the kernel you want to build
 against, use:
 
-KERNELDIR=path_to_kernel_dir make
-KERNELDIR=path_to_kernel_dir make modules_install
+% KERNELDIR=path_to_kernel_dir make
+# KERNELDIR=path_to_kernel_dir make modules_install
 
-Use lttng-tools (git://git.lttng.org/lttng-tools.git) to control the tracer.
-LTTng tools should automatically load the kernel modules when needed.
-
-Use Babeltrace (git://git.efficios.com/babeltrace.git) to print traces as a
-human-readable text log.
+Use lttng-tools to control the tracer. LTTng tools should automatically load
+the kernel modules when needed. Use Babeltrace to print traces as a
+human-readable text log. These tools are available at the following URL:
+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 kernels 2.6.38 and 2.6.39 (on x86 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.
+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.