A toolkit for tracing C/C++ program, to generate a time-line based callgraph
A toolkit for tracing C/C++ program(including multi-thread program), it's used to generate a time-line based callgraph, which will guide us to understand the core of the program extremely fast at the beginning.
The devil is in the details...
Imagine that, if there is a 10 years old and huge project will be transferred to us, and the corresponding requirements will come soon as well (like the new features, bug fix..), how can we locate to the core path in a very limited time? So we need a powerful tool to help us. This time-line based callgraph will save us a lot of time to deal with the complex details, we can focus on the more important things, and make the life easier.
And also we can use it as a source code index in the entire working cycles, especially for a very complex program. Everytime we want to remember something from the high level, we can use it, just follow the callgraph flow, to see how it works, as well as we might identify some problems from it :)
There are some existing Callgraphs for the RocksDB, Lua and Redis, we can use them directly without any addtional efforts.
Please note that, the tracer works for us in the following scenarios:
If NOT, we might need some other callgraph tools.
git clone [email protected]:finaldie/ftracer.git
make
To make the tracer working, we should re-compile the application with -g -finstrument-functions
flags
make CFLAGS+="-g -finstrument-functions -O0"
NOTE: Make sure there is no optimization option like -O2
, if exist, replace it with -O0
or just drop it. Btw, we can try the examples in ftracer
PRELOAD ftracer.so in the wrapper script
bash $ cat run.sh
#!/bin/sh
export LD_PRELOAD=/path/to/ftracer.so:libdl.so
./yourapp
Run it
./run.sh
Generate the Report
cd tools
./gen_report.sh -e yourapp -f /tmp/trace.txt
Start tracer when entering into a specific function address
export FTRACER_FUNC_ENTRY=xxx # xxx is the function address, like 0000123
Start tracer when receiving a specific signal
export FTRACER_SIG_NUM=10 # 10 is SIGUSR1, kill -s SIGUSR1 PID to start tracer
Specific a output tracer file
export FTRACER_FILE=/tmp/your_tracer_file
NOTE: About the two features signal
and function address entrance
, they can not enable in the same time, if that, the signal feature will not be take effect.
-e
Program Location
The absolute program path, for example /bin/ls
-f
Raw trace file dumped by the program
By default, the raw trace file is at /tmp/trace.txt
, use -f /tmp/trace.txt
all the time should be OK
-s
Regex Symbol Filter
Sometimes, we deal with C++ programs, there are a lot of noises in there, like std
, boost
... so we should filter them out.
For this, we should use -s
arg, for example:
gen_report.sh -e app -f /tmp/trace.txt -s "^std::"
-S
Filter by file/path
For this, the -S
arg will help us, for example, if we want to filter all the c++ related information out:
gen_report.sh -e app -f /tmp/trace.txt -S /include/c++
-p
Keep at most N level of path
If a path is too long, it will be a noise for us, so the -p parameter will help to keep at most N level of path, for example, there is a path /path/a/b/c/d.c
, use -p 1
the path in the report will be c/d.c
.
If no -p
or -p
value is a negative number, this feature will be ignored
-o
Specific output folder
The default output folder is /tmp
, but if we want to specific another folder,
-o output
will help us.
-d
Don't cleanup the temporay data
If we get some wrong data when running gen_report.sh
, the temporay data will help us to debug what's happened, so if we want to debug it, pass the -d
paramter.
-r
Read symbols from the dynamic libraries
Most of the time, we only care about the symbols from the program itself, but in case we want to read the symbols from the dynamic libraries, enable this flag then. Please note, enable this flag will slow down the report generation.
-v
Show debug info
If we need more information during the report generating, pass -v
in
-t
Start N process to generate report
The addr2line is slow, sometimes we need to start N processes to generate the report in parallel, it will reduce the generating time. For example -t 4
-F
output format
Default output format is plain
, and we also can specific html
format, for example -F html
, this will be greatly helpful when we are dealing with a very big call graph. Lua5.3.3 Callgraph
For now, open the /tmp/trace_report.txt.threadid
and enjoy it. The example like:
1x main(/home/username/github/ftracer/example/test.c:44) - (called from ??:0)
.. 3x a(/home/username/github/ftracer/example/test.c:36) - (called from test.c:45)
.... 1x b(/home/username/github/ftracer/example/test.c:21) - (called from test.c:39)
...... 1x c(/home/username/github/ftracer/example/test.c:16) - (called from test.c:25)
.... 1x b(/home/username/github/ftracer/example/test.c:21) - (called from test.c:39)
...... 2x d(/home/username/github/ftracer/example/test.c:11) - (called from test.c:27)
...... 1x e(/home/username/github/ftracer/example/test.c:6) - (called from test.c:31)
More detail see the example, and Contact Me, let's do it better :D