Hi Christoph, Thanks for response. Can you please explain in little bit elaborate what do you mean "The value returned from a call to gettid(2) can be passed in the argument pid. Specifying pid as 0 will set the attribute for the calling thread, and passing the value returned from a call to getpid(2) will set the attribute for the main thread of the thread group." To whom I should pass the id. I did not understood. Thanks, Sri. On Fri, Feb 4, 2011 at 2:29 PM, Christoph Lameter <cl@xxxxxxxxx> wrote: > On Fri, 4 Feb 2011, Sri Ram Vemulpali wrote: > >> I have doubt regarding how the thread affinity (to processor) is >> defined in a process (task). If there is only single thread in a >> process, then when process calls itself on binding to a core, will let >> run on that core forever. But, what if there are multiple threads, in >> a process (task). If the main thread calls set affinity to a core, is >> it going to get inherited to all other threads, or just the calling >> thread in a task. What happens when forked a process with threads that >> has affinity to a core. Please can anyone point me to the literature >> on this. Thanks in advance. > > See "man sched_setaffinity" > > " > The affinity mask is actually a per-thread attribute that can be > adjusted independently for each of the threads in a thread group. The > value returned from a call to gettid(2) can be passed in the argument > pid. Specifying pid as 0 will set the attribute for the calling thread, > and passing the value returned from a call to getpid(2) will set the > attribute for the main thread of the thread group. (If you are using > the POSIX threads API, then use pthread_setaffinity_np(3) instead of > sched_setaffinity().) > " > > > > The setting of the affinity occurs for the running thread if pid == 0. > Affinity masks are inherited across forks. > > > > > > -- Regards, Sri. _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
