Hello,
Jeff Squyres wrote:
> I think you're looking at an older version of PLPA -- this issue was
> raised in mid-January (see http://www.open-mpi.org/community/lists/
> plpa-users/2006/01/0012.php) and I released v1.0.1 with cpusetsize
> clarified to be in units of bytes (and fixed a few of the tests as
> you noted). I also added a short bit in the README about the units
> of cpusetsize:
>
> The units of cpusetsize is number of bytes. This should normally
> just be sizeof(*cpuset), but is made available as a parameter to
> allow for future expansion of the PLPA (stay tuned).
oh, i must missed this, but good to know, that we are on the same site
>
> Can you verify that you're at the most recent version (1.0.2)?
>
yes i can:
$ wget http://www.open-mpi.org/software/plpa/downloads/plpa-1.0.2.tar.bz2
$ tar xjf plpa-1.0.2.tar.bz2
$ cd plpa-1.0.2/src/libplpa
$ grep -nr PLPA_BITMASK_NUM_ELEMENTS plpa_dispatch.c
34: if (cpusetsize > PLPA_BITMASK_NUM_ELEMENTS) {
126: if (PLPA_NAME(len) > PLPA_BITMASK_NUM_ELEMENTS) {
and also the odd things with PLPA_NAME(len) used as bits (line 64 and 72) are
still in
bert wesarg
>
> On Feb 12, 2006, at 11:17 AM, Bert Wesarg wrote:
>
>> Hello list,
>>
>> i'm a little confused by the 'cpusetsize' argument to
>> sched_setaffinity().
>> i found the following in your code
>>
>> from plpa-1.0.2/src/libplpa/plpa_dispatch.c:
>>> 32: case PLPA_PROBE_OK:
>>> 33: /* This shouldn't happen, but check anyway */
>>> 34: if (cpusetsize > PLPA_BITMASK_NUM_ELEMENTS) {
>> here 'cpusetsize' is asumed to be a number of 'unsigned long int'
>> for the
>> 'struct cpu_set_t'
>>
>>> 35: return EINVAL;
>>> 36: }
>>> 48: if (cpusetsize < PLPA_NAME(len)) {
>> 'cpusetsize' and 'len' is assumed to be the number of bits
>>
>>> 49: memset(&tmp, 0, sizeof(tmp));
>>> 50: for (i = 0; i < cpusetsize * 8; ++i) {
>> 'cpusetsize' is assumed to be a number of bytes
>>
>>> 51: if (PLPA_CPU_ISSET(i, cpuset)) {
>>> 52: PLPA_CPU_SET(i, &tmp);
>>> 53: }
>>> 54: }
>>> 55: }
>>> 63: else if (cpusetsize > PLPA_NAME(len)) {
>> same as in line 48
>>
>>> 64: for (i = PLPA_NAME(len); i < cpusetsize * 8; ++i) {
>> 'len' number of bits, 'cpusetsize' number of bytes
>>
>>> 65: if (PLPA_CPU_ISSET(i, cpuset)) {
>>> 66: return EINVAL;
>>> 67: }
>>> 71: memset(&tmp, 0, sizeof(tmp));
>>> 72: for (i = 0; i < PLPA_NAME(len); ++i) {
>> 'len' is assumed to be the number of bits
>>
>>> 73: if (PLPA_CPU_ISSET(i, cpuset)) {
>>> 74: PLPA_CPU_SET(i, &tmp);
>>> 75: }
>>> 76: }
>>> 77: }
>>> 78:
>>> 79: /* Otherwise, the user supplied a buffer that is
>>> exactly the
>>> 80: right size. Just for clarity of code, copy the user's
>>> 81: buffer into the temporary and use that. */
>>> 82: else {
>>> 83: memcpy(&tmp, cpuset, cpusetsize);
>> 'cpusetsize' number of bytes
>>> 84: }
>>> 85:
>>> 86: /* Now do the syscall */
>>> 87: ret = syscall(__NR_sched_setaffinity, 0, PLPA_NAME
>>> (len), &tmp);
>> at least my kernel (2.6.14) expects the 'len' parameter to be the
>> number
>> of bytes (sizeof(cpu_set_t)):
>>
>> from kernel/sched.c:
>> static int get_user_cpu_mask(unsigned long __user *user_mask_ptr,
>> unsigned
>> len,
>> cpumask_t *new_mask)
>> {
>> if (len < sizeof(cpumask_t)) {
>> memset(new_mask, 0, sizeof(cpumask_t));
>> } else if (len > sizeof(cpumask_t)) {
>> len = sizeof(cpumask_t);
>> }
>> return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
>> }
>>
>> /**
>> * sys_sched_setaffinity - set the cpu affinity of a process
>> * @pid: pid of the process
>> * @len: length in bytes of the bitmask pointed to by user_mask_ptr
>> * @user_mask_ptr: user-space pointer to the new cpu mask
>> */
>> asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len,
>> unsigned long __user *user_mask_ptr)
>> {
>> cpumask_t new_mask;
>> int retval;
>>
>> retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask);
>> if (retval)
>> return retval;
>>
>> return sched_setaffinity(pid, new_mask);
>> }
>>
>> i count 3 'definitions' for 'cpusetsize'! my question is wich
>> 'definition'
>> should i use for the call to PLPA_NAME(sched_setaffinity)()? i
>> can't find
>> even a definition in any documentation from the package!
>>
>> best regards
>> bert wesarg
>>
>> _______________________________________________
>> plpa-users mailing list
>> plpa-users_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/plpa-users
>
>
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