Gleipnir How-To Guide

If you are unfamiliar with Valgrind we suggest that you at least get a basic understanding of how Valgrind works.

Basic Run

Let's get a basic understanding of Gleipnir's output by running the following code:

#include <stdio.h>
//#include <set path to gleipnir.h>

struct typeA {
     double var1;
     int myArray[10];
};
 
struct typeA GlStrc;
struct typeA GlStrcArray[10];

int GlScalar;
int GlArray[10];

void func(struct typeA StrcParam[]);

int main(void)
{
    GLEIPNIR_START_INSTRUMENTATION;

	struct typeA LoStrcArray[5];

    int i, LoScalar;
    int LoArray[10];

    GlScalar = 321;
    LoScalar = 123;

    for(i=0; i<2; i++)
        LoArray[i] = GlScalar;

    func(LoStrcArray);

    return 0;

	GLEIPNIR_STOP_INSTRUMENTATION;
}

void func(struct typeA StrcParam[])
{
    int i;

    for(i=0; i<2; i++){
        GlStrcArray[i].var1 = GlScalar;
        GlStrcArray[i].myArray[0] = GlArray[0];

        StrcParam[i].var1 = GlArray[i];
    }

	return;
}

Compile the code with debug options enabled

 $ gcc -g code.c -o code.out

Assuming everything compiled and is running you can run gleipnir as follows:

 $ $valgrind/src/bin/valgrind --read-var-info=yes --tool=gleipnir ./path/code.out

You should see the following output

==25149== Gleipnir, a Valgrind tool
==25149== Copyright (C) 2010-2011, and GNU GPL'd, by Tommy Janjusic and Brandon Potter.
==25149== Using Valgrind-3.7.0.SVN and LibVEX; rerun with -h for copyright info
==25149== Command: /home/janjust/research/tests/random_tests/code.out
==25149== 
==25149==

Gleipnir will generate a trace file in the form gleipnir.pid; where pid is the process ID.

==25149== 
janjust@fenrir:~/research/valgrind_build/bin$ ls
callgrind_annotate  callgrind_control  cg_annotate  cg_diff  cg_merge  gleipnir.out.25149  ms_print  valgrind  valgrind-listener  vgdb
janjust@fenrir:~/research/valgrind_build/bin$

The trace files can get rather large, this simple program produced a ~4MB trace file with roughly ~150k lines.
These traces are Load, Store and Instruction traces interleaved, if it is of little interest then the Instruction traces may be suppressed.

To get an idea of Gleipnir's output, look at the trace snippet below:

153945 I 004004b4 main
153946 S 7fefff9f0 main
153947 I 004004b5 main
153948 I 004004b8 main
153949 I 004004bf main
153950 S 00601040 main
153951 I 004004c9 main
153952 S 7fefff9e8 main LV 0 1 LoScalar
153953 I 004004d0 main
153954 S 7fefff9ec main LV 0 1 i
153955 I 004004d7 main
153956 I 004004ec main
153957 L 7fefff9ec main LV 0 1 i
153958 I 004004f0 main
153959 I 004004d9 main
153960 L 7fefff9ec main LV 0 1 i
153961 I 004004dc main
153962 L 00601040 main
153963 I 004004e2 main
153964 I 004004e4 main
153965 S 7fefff9c0 main LS 0 1 LoArray[0]
153966 I 004004e8 main
153967 M 7fefff9ec main LV 0 1 i
153968 I 004004ec main
153969 L 7fefff9ec main LV 0 1 i
153970 I 004004f0 main
153971 I 004004d9 main
153972 L 7fefff9ec main LV 0 1 i
153973 I 004004dc main
153974 L 00601040 main
153975 I 004004e2 main
153976 I 004004e4 main
153977 S 7fefff9c4 main LS 0 1 LoArray[1]
153978 I 004004e8 main
153979 M 7fefff9ec main LV 0 1 i
153980 I 004004ec main
153981 L 7fefff9ec main LV 0 1 i
153982 I 004004f0 main
153983 I 004004f2 main
153984 I 004004f9 main
153985 I 004004fc main
153986 S 7fefff8c8 main
153987 I 00400508 func
153988 S 7fefff8c0 func
153989 I 00400509 func
153990 I 0040050c func
153991 S 7fefff8a8 func LV 0 1 StrcParam
153992 I 00400510 func
153993 S 7fefff8bc func LV 0 1 i
153994 I 00400517 func
153995 I 0040058d func
153996 L 7fefff8bc func LV 0 1 i
153997 I 00400591 func
153998 I 00400519 func
153999 L 7fefff8bc func LV 0 1 i
154000 I 0040051c func
154001 L 00601040 func
154002 I 00400522 func
154003 I 00400526 func
154004 I 00400529 func
154005 I 0040052c func
154006 I 0040052f func
154007 I 00400532 func
154008 I 00400536 func
154009 S 00601060 func
154010 I 0040053e func
154011 L 7fefff8bc func LV 0 1 i
154012 I 00400541 func
154013 L 00601240 func
154014 I 00400547 func
154015 I 0040054a func
154016 I 0040054d func
154017 I 00400550 func
154018 I 00400553 func
154019 I 00400557 func
154020 S 00601068 func
154021 I 0040055d func
154022 L 7fefff8bc func LV 0 1 i
154023 I 00400560 func
154024 I 00400563 func
154025 I 00400566 func
154026 I 00400569 func
154026 I 00400569 func
154027 I 0040056c func
154028 I 00400570 func
154029 L 7fefff8a8 func LV 0 1 StrcParam
154030 I 00400574 func
154031 L 7fefff8bc func LV 0 1 i
154032 I 00400577 func
154033 I 0040057a func
154034 L 00601240 func
154035 I 00400581 func
154036 I 00400585 func
154037 S 7fefff8d0 func LS 1 1 LoStrcArray[0].var1
154038 I 00400589 func
154039 M 7fefff8bc func LV 0 1 i
154040 I 0040058d func
154041 L 7fefff8bc func LV 0 1 i
154042 I 00400591 func
154043 I 00400519 func
154044 L 7fefff8bc func LV 0 1 i
154045 I 0040051c func
154046 L 00601040 func
154047 I 00400522 func
154048 I 00400526 func
154049 I 00400529 func
154050 I 0040052c func
154051 I 0040052f func
154052 I 00400532 func
154053 I 00400536 func
154054 S 00601090 func
154055 I 0040053e func
154056 L 7fefff8bc func LV 0 1 i
154057 I 00400541 func
154058 L 00601240 func
154059 I 00400547 func
154060 I 0040054a func
154061 I 0040054d func
154062 I 00400550 func
154063 I 00400553 func
154064 I 00400557 func
154065 S 00601098 func
154066 I 0040055d func
154067 L 7fefff8bc func LV 0 1 i
154068 I 00400560 func
154069 I 00400563 func
154070 I 00400566 func
154071 I 00400569 func
154072 I 0040056c func
154073 I 00400570 func
154074 L 7fefff8a8 func LV 0 1 StrcParam
154075 I 00400574 func
154076 L 7fefff8bc func LV 0 1 i
154077 I 00400577 func
154078 I 0040057a func
154079 L 00601244 func
154080 I 00400581 func
154081 I 00400585 func
154082 S 7fefff900 func LS 1 1 LoStrcArray[1].var1
154083 I 00400589 func
154084 M 7fefff8bc func LV 0 1 i
154085 I 0040058d func
154086 L 7fefff8bc func LV 0 1 i
154087 I 00400591 func
154088 I 00400593 func
154089 L 7fefff8c0 func
154090 I 00400594 func
154091 L 7fefff8c8 func
154092 I 00400501 main
154093 I 00400506 main
154094 L 7fefff9f0 main
154095 I 00400507 main
154096 L 7fefff9f8 main

The traces are all the instructions (and a few extra :-/) which were executed during the code.out program run. Their virtual addresses are mapped back to their source code variables. The idea is to use these traces in trace driven cache simulators to produce graphical analyses of an application's cache behavior.

As part of the Gleipnir tool-set we have modified DineroIV for our purposes of cache simulation.