Hi everybody.
I am profiling an MP3 decoding on an ARM9-based processor, and using kernel 2.6.20

When I set --no-vmlinux I have a reasonable number of samples (14/15 k) in 2 minutes of test.
When specifying the vmlinux image it can't get more than 600 samples in the same time.
It seems like it looses some samples.

Where could the problem be?
I set the kernel_range manually in opcontrol (sh script), since the environment in which I run it uses busybox which does not implement completely some functionalities, could the problem lie in this?


Here I paste the 2 different results i get from the 2 tests.

(cm is a kernel module)

/host # opreport
CPU: CPU with timer interrupt, speed 0 MHz (estimated)
Profiling through timer interrupt
          TIMER:0|
  samples|      %|
------------------
    12854 90.4765 no-vmlinux
      635  4.4696 mp3decoder
                  TIMER:0|
          samples|      %|
        ------------------
              516 81.2598 no-vmlinux
               77 12.1260 mp3decoder
               26  4.0945 libpthread-2.5.so
               16  2.5197 libc-2.5.so
      446  3.1393 aplay
                  TIMER:0|
          samples|      %|
        ------------------
              279 62.5561 libasound.so.2.0.0
              155 34.7534 no-vmlinux
               10  2.2422 libc-2.5.so
                2  0.4484 aplay
      266  1.8723 busybox
                  TIMER:0|
          samples|      %|
        ------------------
              214 80.4511 no-vmlinux
               22  8.2707 ld-2.5.so
               15  5.6391 libc-2.5.so
               14  5.2632 busybox
                1  0.3759 libcrypt-2.5.so
        4  0.0282 ophelp
                  TIMER:0|
          samples|      %|
        ------------------
                3 75.0000 no-vmlinux
                1 25.0000 ld-2.5.so
        2  0.0141 busybox
                  TIMER:0|
          samples|      %|
        ------------------
                1 50.0000 no-vmlinux
                1 50.0000 ld-2.5.so


/host # opreport
CPU: CPU with timer interrupt, speed 0 MHz (estimated)
Profiling through timer interrupt
          TIMER:0|
  samples|      %|
------------------
      288 52.9412 aplay
                  TIMER:0|
          samples|      %|
        ------------------
              281 97.5694 libasound.so.2.0.0
                5  1.7361 libc-2.5.so
                1  0.3472 aplay
                1  0.3472 ld-2.5.so
      182 33.4559 mp3decoder
                  TIMER:0|
          samples|      %|
        ------------------
               74 40.6593 mp3decoder
               62 34.0659 cm
               31 17.0330 libpthread-2.5.so
               14  7.6923 libc-2.5.so
                1  0.5495 ld-2.5.so
       55 10.1103 busybox
                  TIMER:0|
          samples|      %|
        ------------------
               20 36.3636 ld-2.5.so
               18 32.7273 libc-2.5.so
               16 29.0909 busybox
                1  1.8182 libm-2.5.so
       19  3.4926 cm


Thanks a lot.