[cairo-bugs] [Bug 66783] cairo-perf does not deal with cpus larger then 1024 well.

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=66783

--- Comment #2 from Nathan Zimmer <nzimmer at sgi.com> ---
Ah, you are correct I was misreading the code.

>If CPU_SETSIZE doesn't match the value as used by the kernel, sched_getaffinity() is meant >to return -EINVAL. Is that the case on your system?

They don't need to match but the user does need to provide enough space for the
bitmask.
So it works fine on systems where CPU_SETSIZE is greater then or equal to the
number of configured cpus.

I don't think ignoring a error status is wise.

If you don't think the check is needed that would be fine by me.

But if someone is insistent here are the two standard ways I found:

#ifdef _SC_NPROCESSORS_CONF
        int nrcpus = sysconf(_SC_NPROCESSORS_CONF);
        cpu_set_t * cpu_mask;
        cpu_mask = CPU_ALLOC(nrcpus);
        mask_size = CPU_ALLOC_SIZE(nrcpus);
        sched_getaffinity(0, mask_size, &cpu_mask);
        cpu_count = CPU_COUNT_S(mask_size, cpu_mask);
        CPU_FREE(cpu_mask);
#endif

or if someone has and aversion to _SC_NPROCESSORS_CONF

        int nrcpus = 1024;
realloc:
        cpus = CPU_ALLOC(nrcpus);
        size = CPU_ALLOC_SIZE(nrcpus);
        CPU_ZERO_S(size, cpus);

        if (sched_getaffinity(0, size, cpus)) {
                if( errno == EINVAL && nrcpus < (4096<<4) ) {
                        CPU_FREE(cpus);
                        nrcpus <= 1;
                        goto realloc;
                }
                fatal("sched_getaffinity", ERR_SYSCALL, "Can't get CPU
info\n");
        }
        cpu_count = CPU_COUNT_S(size, cpus);
        CPU_FREE(cpus);

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