Tools in Linux

Posted on 28 Sep 2016 in Technology


Overview

Tux

Imagine a situation with no tools available to check a system’s performance, when it comes to an Embedded system engineer. Especially, with operating systems like Linux. There are hell lot of tools now at our service. But during the ages of initial Linux Kernel developement, think about how system analysis had been done. This post is to throw some light over the tools that are available for us to poke the system at right places and see how it behaves.

Tools Category

There are several categories and number of tools under each category.

Categories Tools
Debugging GDB
strace
pmap
pstack
mtrace
Profiling OProfile
Perf
gprof
memprof
Tracing ftrace
Lttng
System map
dtrace
Analyzing  
(i) Resource Analyzing valgrind
(ii) Process Analyzing proc tools
vmstat
procstat
Coverage gcov
Benchmarking LMbench
IOzone
memtester
flashbench
fio
Additional tools stress-app test
measuretime
grabserial
linux-serial-test

Debugging

The tools here are helpful when we are in need of understanding what is going on while the executing a program that is holding the computer with itself. The sequence of system calls, memory it consumes and so on can be traced using the following tools.

Tool Description
GDB the GNU Project debugger, allows you to see what is going on inside an other program while it executes-or what another program was doing at the moment it crashed.
strace runs the specified command until it exits. It intercepts and records the system calls which are called by a process and the signals which are received by a process.
pmap reports the memory map of the process
pstack attaches to the active processes named by the pids on the commandline, and prints out an execution stack trace, including a hint at what the function arguments are.
mtrace memory debugger included in GNU C library. The handlers log all memory allocations and frees to a file.

Profiling

Tool Description
oprofile OProfile is a system-wide profiler for Linux systems, capable of profiling all running code at low overhead. OProfile leverages the hardware performance counters of the CPU to enable profiling of a wide variety of interesting statistics, which can also be used for basic time-spent profiling.
perf It is capable of statistical profiling of entire system (both kernel and user code), single CPU or several threads.
gprof a performance analyzing tool in Unix. It uses a hybrid variety of instrumentaion and sampling. It is an extension of the older prof Unix tool. Unlike prof, gprof is capable of limited call graph printing.
memprof tool for profiling memory usage and finding memory leaks.

Tracing

Tool Description
ftrace A Linux kernel internal tracer. It includes function tracer. ftrace is named after it.
Lttng The LTTng project aims at providing highly efficient tracing tools for Linux. Its tracers help tracking down performance issues and debugging problems involving multiple concurrent processes and threads. Tracing across multiple systems is also possible.
System tap Assists the diagnosis of a performance or functional problem. Reduces the developers process sequences to collect performance data.
dtrace A comprehensive dynamic tracing framework for troubleshooting kernel and application problems on production systems in real time.

Analyzing

Resource Analyzing
Tool Description
Valgrind Instrumentation framework for building dynamic analysis tools.
Helgrind A Valgrind tool for detecting synchronisation errors in C, C++ and Fortran programs that use the POSIX pthreads threading primitives.
Process Analyzing
Tool Description
proc tools The proc tools are utilities that exercise features of /proc
vmstat Reports information about processes, memory, paging, block IO, traps, and cpu activity.
procstat Displays detailed information about the processes identified by the pid arguments or all processes.

Coverage

Tool Description
gcov A test coverage program. Use it in concert with GCC to analyze programs to help create more efficient, faster running code and to discover untested parts of the program.

Benchmarking

Tool Description
LMbench A benchmarking tool for bandwidth, latency and processor clock rate etc.
IOzone A filesystem benchmark tool. The benchmark generates and measures a variety of file operations. Iozone has been ported to many machines and runs under many operating systems.
memtester DDR testing benchmark.
flashbench Flash benchmarking.
fio Flash benchmarking.

Additional tools

Tool Description
stress-app test Stressful Application Test (or stressapptest, its unix name) tries to maximize randomized traffic to memory from processor and I/O, with the intent of creating a realistic high load situation in order to test the existing hardware devices in a computer. It has been used at Google for some time and now it is available under the apache 2.0 license.
measuretime Timing analysis.
grabserial Boottime analysis, grabs the serial console with respect to pattern and time.
linux-serial-test For serial bandwidth testing.
smem Gives numerous reports on memory usage in Linux system.
SYSSTAT Contains utilities to monitor system performance and usage activities.

Usage and Risks

  • These tools provide better grounds for delivering a quality software.
  • Tests the corner cases.
  • Traces the memory leaks, buffer overflow etc.,
  • Produces the performance data in both system level and application level.
  • Using these tools need understanding of its benefits, Knowledge of when, where and how to use them.
  • These tools require configurations and particular coding style, which increases the size of the binary compiled. This means we need to have a provision of debug and release flags in the code.
  • The best approach would be to use these tools from the development phase itself.

Proposed methodologies

  • To use QEMU, and Eclipse based build and testing platform during developement phase itself.

Known Issues

  • sftp-server is needed for transferring the information between target and host for any profiling / debugging tool.
  • oprofile-server in target and oprofile-viewer(eclipse) in host are needed for viewing the report in graphical format.

Solution

  • We should cross compile sftp-server from openssh source and placed it in target (/usr/libexec/sftp-server). This location is mandatory because eclipse searches for this path.
  • oprofile-server is cross-compiled for target and oprofile-viewer is compiled and install in host.

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