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Andrew Lutomirski authored
Perf can't currently trace into the vsyscall page. It looks like it was meant to work. Tested on 2.6.38 and today's -git. The bug is easy to reproduce. Compile this: int main() { int i; struct timespec t; for(i = 0; i < 10000000; i++) clock_gettime(CLOCK_MONOTONIC, &t); return 0; } and run it through perf record; perf report. The top entry shows "[unknown]" and you can't zoom in. It looks like there are two issues. The first is a that a test for user mode executing in kernel space is backwards. (That's the first hunk below). The second (I think) is that something's wrong with the code that generates lots of little struct dso objects for different sections -- when it runs on vmlinux it results in bogus long_name values which cause objdump to fail. Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LPU-Reference: <AANLkTikxSw5+wJZUWNz++nL7mgivCh_Zf=2Kq6=f9Ce_@mail.gmail.com> Signed-off-by: Andy Lutomirski <luto@mit.edu> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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