[OpenIndiana-discuss] OI on modern Intel with P-cores and E-cores?

[Bill Sommerfeld]

On 4/19/26 22:53, Tim Mooney via openindiana-discuss wrote:
> Anyone know how well Illumos handles modern Intel CPUs with different
> types of cores (performance cores, aka P-cores, and efficiency cores,
> aka E-cores)?
> 
> I'm specifically looking at Core Ultra 7 265K, which is/was "Arrow Lake"
> I think, and has 8 P-cores and 12 E-cores.
> 
> If anyone is using current OI on a recent Intel with varying types of
> cores, I would be interested to hear how it's working.

With respect to Intel systems with a mix of P and E cores, I have a 
system with an i5-1235U ("12th generation Alder Lake" which is I think 
~2 generations older than "Arrow Lake").   It's behaving itself with all 
cores running (2 P cores, 8 E cores), acting primarily as a router, dhcp 
server, and dns resolver:

$ psrinfo -pv
The physical processor has 10 cores and 12 virtual processors (0-11)
   The core has 2 virtual processors (0-1)
   The core has 2 virtual processors (2-3)
   The core has 1 virtual processors (4)
   The core has 1 virtual processors (5)
   The core has 1 virtual processors (6)
   The core has 1 virtual processors (7)
   The core has 1 virtual processors (8)
   The core has 1 virtual processors (9)
   The core has 1 virtual processors (10)
   The core has 1 virtual processors (11)
     x86 (GenuineIntel 906A4 family 6 model 154 step 4 clock 2500 MHz)
       12th Gen Intel(r) Core(tm) i5-1235U

My understanding is that the illumos scheduler isn't following best 
practices for P vs E (which is to first use first thread of P cores, 
then E cores, then the 2nd thread of P cores), but it also looks like 
intel is no longer offering hyperthreaded P cores in Arrow Lake.

So it should work but may not perform as well as it could with a bit 
more intelligence in the scheduler.

					- Bill