Profiling of vdso_test_random

[Christophe Leroy <christophe.leroy@csgroup.eu>]

Hi,

I'm done a 'perf record' on vdso_test_random reduced to vdso test only, 
and I get the following function usage profile.

Do you see the same type of percentage on your platforms ?

I would have expected most of the time to be spent in 
__arch_chacha20_blocks_nostack() but that's in fact not the case.

# Samples: 61K of event 'task-clock:ppp'
# Event count (approx.): 15463500000
#
# Overhead  Command          Shared Object        Symbol 

# ........  ...............  ................... 
....................................
#
     57.74%  vdso_test_getra  [vdso]               [.] __c_kernel_getrandom
     22.49%  vdso_test_getra  [vdso]               [.] 
__arch_chacha20_blocks_nostack
     10.80%  vdso_test_getra  vdso_test_getrandom  [.] test_vdso_getrandom
      8.89%  vdso_test_getra  [vdso]               [.] __kernel_getrandom
      0.01%  vdso_test_getra  [kernel.kallsyms]    [k] 
finish_task_switch.isra.0


Christophe