Valgrind

• /usr/share/doc/valgrind-version/valgrind_manual.pdf
• /usr/share/doc/valgrind-version/html/index.html

Memcheck is the default Valgrind tool, and can be run with valgrind program, without specifying --tool=memcheck.

valgrind --leak-check=full myprog arg1 arg2
valgrind --leak-check=full --log-file="logfile.out" -v myprog arg1

Some of the options available are:

• –leak-check When enabled, Memcheck searches for memory leaks when the client program finishes. The default value is summary, which outputs the number of leaks found. Other possible values are yes and full, both of which give details of each individual leak, and no, which disables memory leak checking.
• –undef-value-errors When enabled (set to yes), Memcheck reports errors when undefined values are used. When disabled (set to no), undefined value errors are not reported. This is enabled by default. Disabling it speeds up Memcheck slightly.
• –ignore-ranges Allows the user to specify one or more ranges that Memcheck should ignore when checking for addressability. Multiple ranges are delimited by commas, for example, --ignore-ranges=0xPP-0xQQ,0xRR-0xSS.

# valgrind --tool=cachegrind program

Cachegrind can gather the following statistics for the entire program, and for each function in the program:

• first-level instruction cache reads (or instructions executed) and read misses, and last-level cache instruction read misses;
• data cache reads (or memory reads), read misses, and last-level cache data read misses;
• data cache writes (or memory writes), write misses, and last-level cache write misses;
• conditional branches executed and mispredicted; and
• indirect branches executed and mispredicted.

his file can be further processed by the accompanying cg_annotate tool, like so:

# cg_annotate cachegrind.out.pid

You can also compare the profile files created by Cachegrind to make it simpler to chart program performance before and after a change.

# cg_diff first second

valgrind --tool=massif  myprog

Profiling data gathered by Massif is written to a file, which by default is called massif.out.pid, where pid is the process ID of the specified program.

This profiling data can also be graphed with the ms_print command, like so:

# ms_print massif.out.pid

This produces a graph showing memory consumption over the program's execution,

massiftool is used to present it in a graphical form, which can be downloaded from http://sourceforge.net/projects/massiftool/. Note that massiftool requries version 4.6 or higher of the Qt library.

Some of the available options are:

• –heap Specifies whether to perform heap profiling. The default value is yes. Heap profiling can be disabled by setting this option to no.
• –heap-admin Specifies the number of bytes per block to use for administration when heap profiling is enabled. The default value is 8 bytes per block.
• –stacks Specifies whether to perform stack profiling. The default value is no (disabled). To enable stack profiling, set this option to yes, but be aware that doing so will greatly slow Massif. Also note that Massif assumes that the main stack has size zero at start-up in order to better indicate the size of the stack portion over which the program being profiled has control.
• –time-unit Specifies the unit of time used for the profiling. There are three valid values for this option: instructions executed (i), the default value, which is useful in most cases; real time (ms, in milliseconds), which can be useful in certain instances; and bytes allocated/deallocated on the heap and/or stack (B), which is useful for very short-run programs, and for testing purposes, because it is the most reproducible across different machines. This option is useful when graphing Massif output with ms_print.