1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/src/devtools/vprof/readme.txt Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,97 @@
1.4 +# This Source Code Form is subject to the terms of the Mozilla Public
1.5 +# License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 +# file, You can obtain one at http://mozilla.org/MPL/2.0/.
1.7 +
1.8 +The two files vprof.h and vprof.cpp implement a simple value-profiling mechanism. By including these two files in avmplus (or any other project), you can value profile data as you wish (currently integers).
1.9 +
1.10 +Usage:
1.11 +#include "vprof.h" // in the source file you want to use it
1.12 +
1.13 +_vprof (value);
1.14 +
1.15 +At the end of the execution, for each probe you'll get the data associated with the probe, such as:
1.16 +
1.17 +File line avg [min : max] total count
1.18 +..\..\pcre\pcre_valid_utf8.cpp 182 50222.75916 [0 : 104947] 4036955604 80381
1.19 +
1.20 +The probe is defined at line 182 of file pcre_vali_utf8.cpp. It was called 80381 times. The min value of the probe was 0 while its max was 10497 and its average was 50222.75916. The total sum of all values of the probe is 4036955604. Later, I plan to add more options on the spectrum of data among others.
1.21 +
1.22 +A few typical uses
1.23 +------------------
1.24 +
1.25 +To see how many times a given function gets executed do:
1.26 +
1.27 +void f()
1.28 +{
1.29 + _vprof(1);
1.30 + ...
1.31 +}
1.32 +
1.33 +void f()
1.34 +{
1.35 + _vprof(1);
1.36 + ...
1.37 + if (...) {
1.38 + _vprof(1);
1.39 + ...
1.40 + } else {
1.41 + _vprof(1);
1.42 + ...
1.43 + }
1.44 +}
1.45 +
1.46 +Here are a few examples of using the value-profiling utility:
1.47 +
1.48 + _vprof (e);
1.49 + at the end of program execution, you'll get a dump of the source location of this probe,
1.50 + its min, max, average, the total sum of all instances of e, and the total number of times this probe was called.
1.51 +
1.52 + _vprof (x > 0);
1.53 + shows how many times and what percentage of the cases x was > 0,
1.54 + that is the probablitiy that x > 0.
1.55 +
1.56 + _vprof (n % 2 == 0);
1.57 + shows how many times n was an even number
1.58 + as well as th probablitiy of n being an even number.
1.59 +
1.60 + _hprof (n, 4, 1000, 5000, 5001, 10000);
1.61 + gives you the histogram of n over the given 4 bucket boundaries:
1.62 + # cases < 1000
1.63 + # cases >= 1000 and < 5000
1.64 + # cases >= 5000 and < 5001
1.65 + # cases >= 5001 and < 10000
1.66 + # cases >= 10000
1.67 +
1.68 + _nvprof ("event name", value);
1.69 + all instances with the same name are merged
1.70 + so, you can call _vprof with the same event name at difference places
1.71 +
1.72 + _vprof (e, myProbe);
1.73 + value profile e and call myProbe (void* vprofID) at the profiling point.
1.74 + inside the probe, the client has the predefined variables:
1.75 + _VAL, _COUNT, _SUM, _MIN, _MAX, and the general purpose registers
1.76 + _IVAR1, ..., IVAR4 general integer registrs
1.77 + _I64VAR1, ..., I64VAR4 general integer64 registrs
1.78 + _DVAR1, ..., _DVAR4 general double registers
1.79 + _GENPTR a generic pointer that can be used by the client
1.80 + the number of registers can be changed in vprof.h
1.81 +
1.82 +Named Events
1.83 +------------
1.84 +_nvprof ("event name", value);
1.85 + all instances with the same name are merged
1.86 + so, you can call _vprof with the same event name at difference places
1.87 +
1.88 +
1.89 +Custom Probes
1.90 +--------------
1.91 +You can call your own custom probe at the profiling point.
1.92 +_vprof (v, myProbe);
1.93 + value profile v and call myProbe (void* vprofID) at the profiling point
1.94 + inside the probe, the client has the predefined variables:
1.95 + _VAL, _COUNT, _SUM, _MIN, _MAX, and the general purpose registers
1.96 + _IVAR1, ..., IVAR4 general integer registrs
1.97 + _I64VAR1, ..., I64VAR4 general integer64 registrs
1.98 + _DVAR1, ..., _DVAR4 general double registers
1.99 + the number of registers can be changed in vprof.h
1.100 + _GENPTR a generic pointer that can be used for almost anything
