![]() ![]() The precise commands I sent to the client are: I asked the customer to crash the application on purpose using SIGABRT when the problems occurs again and send me the coredump. until a bug that was raised from a customer about the system going unresponsive once in a while (could be days) and required reboot. It worked, it was kept like this for few years. they didn’t want to change the architecture so what they did was to emulate the HW timer interrupt using the alarm signal (SIGALRM) Itimer linux software#but when the software was ported to Linux. ![]() We’re working of course on a multi-tasks system that work asynchronously so, a mutex was used to synchronize all of this. and this happens every-time a timer is created, stopped or expire. Itimer linux update#This requires a bit of a bookkeeping, as we need to dynamically update the HW timer whenever a new “closer” timer is scheduled. They did something which is quite usual in embedded world, they created a array of active timers, and always set the HW timer interrupt to occur when the nearest SW timer expires. Itimer linux series#The processor back in the days had a probably a single timer interrupt, so the software team decided to implement over it a series of SW timers. The execution parameters and methods are the same as before.ģ.I came across a very interesting bug that occurred in a Linux software stack that was ported from some kind of embedded processor back in the days. Generally, we can add it to "makefile".Ģ. Add the - pg option when compiling and linking. This call graph also saves all the information related to the function, such as call time, call times, etc.ġ. Itimer linux code#"Annotated source code" can be displayed - it is a copy of the program source code, marked with the execution times of each line of code in the program.īy compiling and linking the program (using the - pg compile and link option), gcc adds a function called mcount (or "_mcount", or "_mcount", which depends on the compiler or operating system) to each function of your application, that is, every function in your application will call mcount, Mcount # will save a function call graph in memory and find the addresses of child functions and parent functions in the form of function call stack. The "Call graph" can be displayed, including the Call relationship of functions and how long each function Call takes.ģ. The "flat profile" can be displayed, including the number of calls of each function and the processor time consumed by each function,Ģ. By default, this tool is included in the linux system.ġ. Gprof , is one of the GNU , GNU , binutils tools. gprof accurately gives the time and number of function calls, and gives the function call relationship. gprof# can accurately analyze performance bottlenecks for programs on Linux platform. GNU compiler toolkit provides a profiling tool GNU profiler (gprof). Improving the performance of an application is a very time-consuming and labor-intensive work, but it is usually not very obvious which functions in the program consume most of the execution time. To produce gmon Out files must be compiled and linked with the - pg - g option.
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