On Fri, Jun 20, 2008 at 06:31:08PM +0530, Sharyathi Nagesh wrote: > Cliff,Andi > > Cliff Wickman wrote: > >> You are using version 1.0.3 I assume. We have 1.0.3-rc1 and 1.0.3-rc2 >> on the download page (ftp://oss.sgi.com/www/projects/libnuma/download). >> I suggest you send me the final form of your patch and I add it and post >> the source as 1.0.3. Sound reasonable? > > I am using still older version of numactl, it is 0.9.6. numactl code base > 1.0.3 has call to move_page system call and this will cause problems that I > have mentioned in previous mail > >>>>>> + cpu_set_t mask; >>>>>> + if( numa_sched_getaffinity(0, sizeof(cpu_set_t), &mask) < 0 ){ >>>>>> + perror("numa_sched_getaffinity:"); > > Ah noticed another problem. Please don't rely on the glibc cpuset_t, > > there's no guarantee it's big enough. > > > In fact libnuma.c already has code for this in set_numa_max_cpu(). > > Please reuse that. Just make sure you don't create a backdoor > > interface into libnuma. > > Andi suggested to used the existing functions to get through the problem, > suggested to use 'set_numa_max_cpu', its equivalent in 0.9.6 version is > 'number_of_configured_cpus'. On using this in util.c to get the maximum cpu > number solves the problem. > > But I was not convinced with the solution, It returns total number of > bytes in cpu mask (bit array) this is not what is expected logically. > So what I am trying to get is - even the latest code doesn't have any > equivalent function which does the work of sysconf(_SC_NPROCESSORS_CONF) > correctly. > Hence we may have to keep the implementation to return the maximum cpu > active, may be pushing it into libnuma.c > Please let me know your thoughts > > Thanks > Sharyathi I agree that the patch from Anton Blanchard fixes the old 0.9.6 version, up thru version 1.0.2 as well. These are available in 1.0.3 and beyond. (from the man page) numa_num_configured_cpus() returns the number of cpus in the system. This count includes any cpus that are currently disabled. This count is derived from the cpu numbers in /sys/devices/system/cpu. If the kernel is configured without /sys (CONFIG_SYSFS=n) then it falls back to using the number of online cpus. numa_num_thread_cpus() returns the number of cpus that the calling thread is allowed to use. This count is derived from the map /proc/self/status, field "Cpus_allowed". Also see the bitmask numa_all_cpus_ptr. But as Andi suggested, why bother with the bugs in old versions? If the issue is just that you are running on a kernel that does not have move_pages(2), what you might do is grab the latest version (numactl-2.0.2) and patch move_pages (in syscall.c) to return an error. -Cliff -- Cliff Wickman Silicon Graphics, Inc. cpw@xxxxxxx (651) 683-3824 -- To unsubscribe from this list: send the line "unsubscribe linux-numa" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
