perf pmu: Improve error messages for missing PMUs

When a PMU is missing print a better error message mentioning
the missing PMU.

% mkdir empty
% mount --bind empty /sys/devices/msr
% perf stat -M Summary true
event syntax error: '{inst_retired.any,cycles}:W,{cpu_clk_unhalted.thread}:W,{inst_retired.any}:W,{cpu_clk_unhalted.ref_tsc,msr/tsc/}:W,{fp_comp_ops_exe.sse_scalar..'
                     \___ Cannot find PMU `msr'. Missing kernel support?

It still cannot find the right column for aliases, but it's already a vast improvement.

v2: Check asprintf

Signed-off-by: Andi Kleen <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

0 files changed, 0 insertions, 0 deletions