kernel_compile_perf_test.md

• compiling with tmpfs

  • vanilla compilation

    Performance counter stats for 'make -j8 vmlinux O=tmpfsdir' (5 runs):
    
    5,648,918,423,621      instructions:u            #    0.84  insn per cycle           ( +-  0.00% )
    6,766,311,303,171      cycles:u                  #    2.280 GHz                      ( +-  0.01% )
      2,969,791.70 msec cpu-clock:u               #    7.652 CPUs utilized            ( +-  0.02% )
    
          388.0829 +- 0.0849 seconds time elapsed  ( +-  0.02% )
    

  • ccache compilation

     Performance counter stats for 'make CC=ccache gcc -fdiagnostics-color -j8 vmlinux O=tmpfsdir' (5 runs):
    
       296,915,633,300      instructions:u            #    0.15  insn per cycle           ( +-521.94% )
       257,195,974,035      cycles:u                  #    0.281 GHz                      ( +-659.55% )
            175,320.10 msec cpu-clock:u               #    1.358 CPUs utilized            ( +-422.77% )
    
                129.14 +- 93.79 seconds time elapsed  ( +- 72.63% )
    

• compiling with gcc plugins + tmpfs

  • vanilla compilation

    Performance counter stats for 'make -j8 vmlinux O=gcctmpfsdir' (5 runs):
    
    5,649,700,549,329      instructions:u            #    0.84  insn per cycle           ( +-  0.00% )
    6,764,241,035,230      cycles:u                  #    2.275 GHz                      ( +-  0.04% )
         2,972,937.03 msec cpu-clock:u               #    7.647 CPUs utilized            ( +-  0.03% )
    
              388.771 +- 0.203 seconds time elapsed  ( +-  0.05% )
    

  • ccache compilation

     Performance counter stats for 'make CC=ccache gcc -fdiagnostics-color -j8 vmlinux O=gcctmpfsdir' (5 runs):
    
       297,937,424,367      instructions:u            #    0.15  insn per cycle           ( +-520.15% )
       258,115,912,747      cycles:u                  #    0.281 GHz                      ( +-657.10% )
            175,597.65 msec cpu-clock:u               #    1.358 CPUs utilized            ( +-422.52% )
    
                129.34 +- 93.89 seconds time elapsed  ( +- 72.59% )
    

• compiling without tmpfs

  • vanilla compilation

     Performance counter stats for 'make -j8 vmlinux O=notmpfsdir' (5 runs):
    
     5,648,825,131,933      instructions:u            #    0.84  insn per cycle           ( +-  0.04% )
     6,763,085,266,445      cycles:u                  #    2.273 GHz                      ( +-  0.02% )
          2,975,753.91 msec cpu-clock:u               #    7.631 CPUs utilized            ( +-  0.03% )
    
               389.959 +- 0.155 seconds time elapsed  ( +-  0.04% )
    

  • ccache compilation

     Performance counter stats for 'make CC=ccache gcc -fdiagnostics-color -j8 vmlinux O=notmpfsdir' (5 runs):
    
       296,700,364,781      instructions:u            #    0.15  insn per cycle           ( +-522.34% )
       257,556,027,350      cycles:u                  #    0.280 GHz                      ( +-658.08% )
            177,850.36 msec cpu-clock:u               #    1.361 CPUs utilized            ( +-416.95% )
    
                130.70 +- 93.83 seconds time elapsed  ( +- 71.79% )
    

• compiling with gcc plugins (no tmpfs)

  • vanilla compilation

     Performance counter stats for 'make -j8 vmlinux O=gccnotmpfsdir' (5 runs):
    
     5,649,556,075,512      instructions:u            #    0.84  insn per cycle           ( +-  0.01% )
     6,761,131,679,935      cycles:u                  #    2.275 GHz                      ( +-  0.03% )
          2,968,912.84 msec cpu-clock:u               #    7.622 CPUs utilized            ( +-  0.08% )
    
               389.524 +- 0.320 seconds time elapsed  ( +-  0.08% )
    

  • ccache compilation

     Performance counter stats for 'make CC=ccache gcc -fdiagnostics-color -j8 vmlinux O=gccnotmpfsdir' (5 runs):
    
       297,193,647,244      instructions:u            #    0.15  insn per cycle           ( +-521.30% )
       258,060,972,662      cycles:u                  #    0.281 GHz                      ( +-656.72% )
            177,624.02 msec cpu-clock:u               #    1.359 CPUs utilized            ( +-416.53% )
    
                130.67 +- 93.70 seconds time elapsed  ( +- 71.70% )