Bert, Thanks for looking the page over. [...] >> The argument >> .I cpusetsize >> is the length (in bytes) of the buffer pointed to by >> .IR cpuset . >> Normally this argument would be specified as >> .IR sizeof(cpu_set_t) . >> The constant >> .B CPU_SETSIZE >> specifies a value one greater than the >> maximum CPU number that can be stored in a CPU set. > Yeah, I like this naming confusion: > > http://sourceware.org/ml/libc-alpha/2008-03/msg00080.html > >> >> For more details on CPU affinity masks, >> as well as a description of a set of macros >> that can be used to manipulate and inspect CPU sets, see >> .BR sched_setaffinity (2) >> for details. >> .SH RETURN VALUE >> On success, these functions return 0; >> on error, they return a non-zero error number. >> .SH ERRORS >> .TP >> .B EFAULT >> A supplied memory address was invalid. >> .TP >> .B EINVAL >> .RB ( pthread_setaffinity_np ()) >> The affinity bit mask >> .I mask >> contains no processors that are physically on the system. >> .TP >> .BR EINVAL >> .RB ( pthread_setaffinity_np ()) >> .I cpuset >> specified a CPU that was outside the range >> permitted by the kernel data type >> .\" cpumask_t >> used to represent CPU sets. >> .\" The raw sched_getaffinity() system call returns the size (in bytes) >> .\" of the cpumask_t type. > Maybe a more detailed hint is needed, that cpumask_t and cpu_set_t are > the 'same', the former inside the kernel the latter in user space. But > I think such deep kernel internals doesn't belong to a API description > (because cpumask_t may gone, see 'struct cpumask' patches). I would > just replace cpumask_t by cpu_set_t. But they are not the same think (which makes things a little weird). The kernel's cpumask_t is typedef struct { DECLARE_BITMAP(bits, NR_CPUS); } cpumask_t; Where NR_CPUS depends on the CONFIG_NR_CPUS config option. But in userspace, cpu_set_t is # define __CPU_SETSIZE 1024 # define __NCPUBITS (8 * sizeof (__cpu_mask)) /* Data structure to describe CPU mask. */ typedef struct { __cpu_mask __bits[__CPU_SETSIZE / __NCPUBITS]; } cpu_set_t; That is, cpu_mask_t is always 1024 bits, but cpumask_t may be (and typically is) smaller. [...] >> .SH SEE ALSO >> .BR sched_getaffinity (2), >> .BR sched_setaffinity (2), >> .BR sched_getscheduler (2), >> .BR pthread_getaffinity_np (3), >> .BR pthread_setaffinity_np (3), > Maybe pthread__attr_{set,get}affinity_np, too. > >> .BR cpuset (7), >> .BR pthreads (7) Good idea. And in fact, I had already changed it to: .SH SEE ALSO .BR sched_getcpu (3), .BR sched_setaffinity (2), .BR sched_setscheduler (2), .BR pthread_attr_setaffinity_np (3), .BR pthread_self (3), .BR cpuset (7), .BR pthreads (7) (Some "get" functions disappeared from the list since they are documented in the corresponding "set" page.) Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ git://git.kernel.org/pub/scm/docs/man-pages/man-pages.git man-pages online: http://www.kernel.org/doc/man-pages/online_pages.html Found a bug? http://www.kernel.org/doc/man-pages/reporting_bugs.html -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
