ubuntu - gprof produce salida vacía

profiling

Question

Estoy ejecutando Ubuntu 16.10 y tratando de perfilar un programa usando gprof. -pg con la bandera -pg y el programa es de un solo hilo. Los comandos de compilación reales son:

g++ -I. -std=c++11 -Wall -Wextra -O3 -pg -fPIC -Wno-unused-parameter -c -o build/obj/performance/stencil_application.o test/performance/stencil_application.cpp
g++ -I. -std=c++11 -Wall -Wextra -O3 -pg -Wno-unused-parameter build/obj/performance/stencil_application.o -o build/test/performance/stencil_application

El programa tarda unos segundos en finalizar cuando lo ejecuto, y se produce un archivo llamado gmon.out. Sin embargo, cuando ejecuto gprof ./build/test/performance/stencil_application , el resultado que obtengo no contiene números. Solo obtengo los encabezados de la tabla y la explicación de los diferentes campos, como este:

Flat profile:

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total           
 time   seconds   seconds    calls  Ts/call  Ts/call  name    

 %         the percentage of the total running time of the
time       program used by this function.

cumulative a running sum of the number of seconds accounted
 seconds   for by this function and those listed above it.

 self      the number of seconds accounted for by this
seconds    function alone.  This is the major sort for this
           listing.

calls      the number of times this function was invoked, if
           this function is profiled, else blank.

 self      the average number of milliseconds spent in this
ms/call    function per call, if this function is profiled,
           else blank.

 total     the average number of milliseconds spent in this
ms/call    function and its descendents per call, if this
           function is profiled, else blank.

name       the name of the function.  This is the minor sort
           for this listing. The index shows the location of
           the function in the gprof listing. If the index is
           in parenthesis it shows where it would appear in
           the gprof listing if it were to be printed.

Copyright (C) 2012-2016 Free Software Foundation, Inc.

Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.

                     Call graph (explanation follows)


granularity: each sample hit covers 2 byte(s) no time propagated

index % time    self  children    called     name

 This table describes the call tree of the program, and was sorted by
 the total amount of time spent in each function and its children.

y así.

También he intentado compilar sin -O3 y con -g , pero con el mismo resultado. ¿Alguien sabe lo que está mal?

Answer 1

Como se señaló en el comentario de Tony Beta Lambda arriba, este es un error en gcc . Hay dos soluciones posibles: degradar a gcc-4.9 o compilar con la bandera -no-pie .