Julie Hartman wrote:
I have a T5240 with 2 CPUs / 8 cores per CPU / 8 threads per core. How do I
turn off threading?
Are you saying that you only want one CPU per core online? Each core
(with 8 threads) is actually comprised of two integer instruction
pipelines, and one floating point pipeline. If you really want only 1
thread online per core, then use psradm(1M) to offline the other logical
CPUs sharing the core:
$ /usr/sbin/psrinfo -vp
The physical processor has 8 cores and 64 virtual processors (0-63)
The core has 8 virtual processors (0-7)
The core has 8 virtual processors (8-15)
The core has 8 virtual processors (16-23)
The core has 8 virtual processors (24-31)
The core has 8 virtual processors (32-39)
The core has 8 virtual processors (40-47)
The core has 8 virtual processors (48-55)
The core has 8 virtual processors (56-63)
UltraSPARC-T2+ (chipid 0, clock 1165 MHz)
The physical processor has 8 cores and 64 virtual processors (64-127)
The core has 8 virtual processors (64-71)
The core has 8 virtual processors (72-79)
The core has 8 virtual processors (80-87)
The core has 8 virtual processors (88-95)
The core has 8 virtual processors (96-103)
The core has 8 virtual processors (104-111)
The core has 8 virtual processors (112-119)
The core has 8 virtual processors (120-127)
UltraSPARC-T2+ (chipid 1, clock 1165 MHz)
...so something along the lines of (for socket 0)
# psradm -f 1-7 9-15 17-23 25-31 33-39 41-47 49-55 57-63
Since there are two integer pipelines per core, you might want to leave
2 CPUs per core online (1 per integer pipeline). In this case, the CPUs
to leave on would be
0, 4, 8, 12, 16, 20, ...
Are you trying to eliminate possible pipeline contention between logical
CPUs?
Thanks,
-Eric
_______________________________________________
perf-discuss mailing list
perf-discuss@opensolaris.org
