source: README @ af4bfd0

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1memlog - A Memory-Allocation Logging Tool
2
3This tool attempts to help you answer the question:
4  Why is my application using so much memory?
5
6** LINKING **
7
8How to use it depends on how your application is linked:
9
10For dynamically-linked applications, you can:
11
12 1. Use LD_PRELOAD: Set LD_PRELOAD=/path/to/memlog/libmemlog.so when you run
13    your application.
14
15 2. Link directly: Add the following to your linker flags:
16      -L/path/to/memlog -Wl,-rpath,/path/to/memlog -lmemlog
17
18For statically-linked applications, add the following to your linker flags:
19
20  -Wl,--wrap,malloc,--wrap,free,--wrap,realloc,--wrap,calloc,--wrap,memalign \
21    /path/to/memlog/memlog_s.o -lpthread -ldl
22
23** RUNNING **
24
25When your application runs, you should find in your current directory files
26named 'HOST.PID.memlog', one for each process. These contain the raw tracing
27information, and are only somewhat human readable. You can create a ps/pdf
28file detailing the memory allocated when each process reached its peak memory
29use by running:
30
31  /path/to/memlog/memlog2dot /path/to/HOST.PID.memlog
32
33this will generate files named HOST.PID.memlog.dot, HOST.PID.memlog.ps and
34HOST.PID.memlog.pdf. You'll probably find the pdf file most convenient for
35viewing.
36
37Note that te peak memory usage is determined by monitoring the processes's
38maximum resident set size, not just the total allocated heap memory.
39
40memlog2dot depends on dot (from the graphviz package) and ps2pdf (from the
41ghostscript package), plus various tools from the binutils package.
42
43** RELATED WORK **
44
45Why was memlog created? There are several other tools that can support this use
46case, but none of them would work in our environment properly. They were
47either too slow, not runnable under the BG/Q CNK, not thread safe, did not
48properly support big-endian PPC64, supported only either static or dynamic
49linking, did not collect full backtraces, or just did not produce
50sufficiently-informative peak-usage output.
51
52That having been said, some other tools that might interest you:
53  Valgrind Massif - http://valgrind.org/docs/manual/ms-manual.html
54  Google Performance Tools - http://google-perftools.googlecode.com/svn/trunk/doc/heapprofile.html
55  memtrail - https://github.com/jrfonseca/memtrail
56  LeakTracer - http://www.andreasen.org/LeakTracer/
57  glibc mtrace - http://www.gnu.org/s/hello/manual/libc/Allocation-Debugging.html
58  Heaptrack - http://milianw.de/blog/heaptrack-a-heap-memory-profiler-for-linux
59  MemProf - http://www.secretlabs.de/projects/memprof/
60
61The dot/pdf output produced by memlog was definitely inspired by that produced
62by Google's pprof tool in the aforementioned package.
63
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