Mark Geisert via Cygwin wrote:
Hi Christian,
On 3/8/2025 9:11 AM, Christian Franke via Cygwin wrote:
Testcase:
$ grep processor /proc/cpuinfo | tail -1 # i7-14700K
processor : 27
$ sleep 60 & taskset 0x1 sleep 60 &
[1] 62094
[2] 62095
$ taskset -p 62094
pid 62094's current affinity mask: fffffff
$ taskset -p 62095
pid 62095's current affinity mask: fffffff
This may well be the first test of Cygwin's affinity support on a
system where the cpu mask bit length isn't a power of 2. I did test
such but seeing it on hardware is another matter.
Are there in fact just 28 hardware processors on this system? ...
One physical cpu with 20 cores and 28 threads (i7-14700K: 8P/HT + 12E)
GetProcessAffinityMask(., ., &sysmask) returns sysmask=0xfffffff
GetProcessGroupAffinity(., &groupcount, grouparray) returns
groupcount=1, grouparray[0] = 0
... Does Windows (or Linux for that matter) allow one to set cpu group
size? I would think the BIOS would want control over that, with the
OSs just providing read access to what was chosen. For 28 processors,
a single group of 28 processors, or either 4 groups of 7 procs, or
7x4, or even 2x14 or 14x2 are plausible if not all useful.
I guess cpu groups are intended to reflect the physical cpus. I don't
know whether this assignment could be changed.
--
Regards,
Christian
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