Including is not required these days, but increases portability. Resource usage metrics are preserved across an execve(2). POSIX.1-2001 specifies getrusage(), but only specifies the fields ru_utime and ru_stime. Usage points outside the accessible address space. On error, -1 is returned, and errno is set appropriately. The number of times a context switch resulted due to a higher priority process becoming runnable or because the current process exceeded its time The number of times a context switch resulted due to a process voluntarily giving up the processor before its time slice was completed (usually to await The number of times the file system had to perform output. The number of times the file system had to perform input. Ru_majflt The number of page faults serviced that required I/O activity. Ru_minflt The number of page faults serviced without any I/O activity here I/O activity is avoided by "reclaiming" a page frame from the list of pages awaiting For RUSAGE_CHILDREN, this is the resident set size of the largest child, not the maximum This is the maximum resident set size used (in kilobytes). Ru_stime This is the total amount of time spent executing in kernel mode, expressed in a timeval structure (seconds plus microseconds). Ru_utime This is the total amount of time spent executing in user mode, expressed in a timeval structure (seconds plus microseconds). (The unmaintained fields are provided for compatibility with other systems,Īnd because they may one day be supported on Linux.) The fields are interpreted as follows: } Not all fields are completed unmaintained fields are set to zero by the kernel. Long ru_nivcsw /* involuntary context switches */ Long ru_nvcsw /* voluntary context switches */ ![]() Long ru_msgrcv /* IPC messages received */ Long ru_oublock /* block output operations */ Long ru_inblock /* block input operations */ Long ru_majflt /* page faults (hard page faults) */ Long ru_minflt /* page reclaims (soft page faults) */ Long ru_isrss /* integral unshared stack size */ Long ru_idrss /* integral unshared data size */ Long ru_ixrss /* integral shared memory size */ Long ru_maxrss /* maximum resident set size */ Struct timeval ru_stime /* system CPU time used */ Struct timeval ru_utime /* user CPU time used */ The resource usages are returned in the structure pointed to by usage, which has the following form: Return resource usage statistics for the calling thread. Resources used by grandchildren, and further removed descendants, if all of the intervening descendants waited on their terminated children. RUSAGE_CHILDREN Return resource usage statistics for all children of the calling process that have terminated and been waited for. RUSAGE_SELF Return resource usage statistics for the calling process, which is the sum of resources used by all threads in the process. Getrusage() returns resource usage measures for who, which can be one of the following: Return (end ->ru_sec - start ->ru_sec) + 1e-6 *(end ->ru_usec - start ->ru_stime.Int getrusage(int who, struct rusage * usage ) Description #include #include #include #include enum įor ( int i = 0 i ru_sec - start ->ru_sec) + 1e-6 *(end ->ru_usec - start ->ru_usec) įloat diffSystemTime( struct rusage *start, struct rusage *end) Since the timeval structure contains two data members - seconds and microseconds to represent time, we implemented the diffUserTime and diffSystemTime functions to calculate elapsed time in seconds. On the other hand, rusage structure should be declared in advance, and the successful function call stores the corresponding values in it. The integer specifies which threads/processes should be measured, and it can have the following predefined macro values RUSAGE_SELF, RUSAGE_CHILDREN or RUSAGE_THREAD. getrusage takes an integer value and an address of the struct rusage object as arguments. The getrusage function retrieves multiple data points about the process, and one of them is system time represented as struc timeval object. The sum of both values is called process time, which is a useful measure when optimizing the program’s performance. The system time represents the period the program executes in kernel mode and user time, denoting the execution time elapsed in user mode. Generally, there are two components of time in any running program. Doc Translator: Как пользоваться переводчиком документов? Use the getrusage Function to Measure System Time of Single-Threaded Program
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |