Upstream fix for OpenBSD cpuid stats #1622
Conversation
| #ifdef __OpenBSD__ | ||
| // HW_NCPUONLINE accounts for hyperthreading off/on | ||
| int mib[2] = { CTL_HW, HW_NCPUONLINE }; | ||
| #else | ||
| int mib[2] = { CTL_HW, HW_NCPU }; |
There was a problem hiding this comment.
perhaps regular linux could use the new constant as well? is it available and kosher?
There was a problem hiding this comment.
Linux seems to use something similar judging from the variable name _SC_NPROCESSORS_ONLN, see https://github.com/beyond-all-reason/spring/blob/BAR105/rts/lib/libcpuid/libcpuid/cpuid_main.c#L253. This segment with HW_NCPU is for various *BSD OS, QNX. Just looking at FreeBSD's sysctl(3) man page, they don't seem to have this kind of MIB entry yet.
| @@ -290,7 +290,12 @@ static bool set_cpu_affinity(logical_cpu_t logical_cpu) | |||
|
|
|||
| static int get_total_cpus(void) | |||
| { | |||
| #ifdef __OpenBSD__ | |||
| // HW_NCPUONLINE accounts for hyperthreading off/on | |||
There was a problem hiding this comment.
| // HW_NCPUONLINE accounts for hyperthreading off/on | |
| // HW_NCPUONLINE accounts for hyperthreading off/on, | |
| // not available on regular linux |
There was a problem hiding this comment.
This isn't related to linux. It looks like linux uses sysconf as I linked above, with different header definitions. This code section is inside:
#if defined __FreeBSD__ || defined __OpenBSD__ || defined __NetBSD__ || defined __bsdi__ || defined __QNX__
In my opinion the HW_NCPUONLINE is clearly enough expressed as OpenBSD-only by the #ifdef __OpenBSD__ right before it, but if you feel strongly that this needs stating, then it should be something like:
// not available on FreeBSD/NetBSD/bsdi/QNX
or
// only available on OpenBSD
There was a problem hiding this comment.
Alright, in that case it's fine as-is IMO.
|
These changes are for libcpuid. Shouldn't these changes be submitted to that project? If we update to a later version we'd need to re-apply these changes? |
|
I will see about approaching upstream libcpuid... |
Use
HW_NCPUONLINEfor OpenBSD CPU count and implementcpu_clock_by_os.HW_NCPUONLINEis the preferred count on OpenBSD;HW_NCPUwould count virtual hyperthreading cores that might be deactivated.