Hi Uladzislau,
On 12/01/26 15:38, Uladzislau Rezki wrote:
On Mon, Jan 12, 2026 at 03:13:33PM +0530, Vishal Chourasia wrote:
Performance data on a PPC64 system with 400 CPUs:
+ ppc64_cpu --smt=1 (SMT8 to SMT1)
Before: real 1m14.792s
After: real 0m03.205s # ~23x improvement
+ ppc64_cpu --smt=8 (SMT1 to SMT8)
Before: real 2m27.695s
After: real 0m02.510s # ~58x improvement
Above numbers were collected on Linux 6.19.0-rc4-00310-g755bc1335e3b
[1]
https://lore.kernel.org/all/5f2ab8a44d685701fe36cdaa8042a1aef215d10d.ca...@linux.vnet.ibm.com
Also you can try: echo 1 >
/sys/module/rcutree/parameters/rcu_normal_wake_from_gp
to speedup regular synchronize_rcu() call. But i am not saying that it would
beat
your "expedited switch" improvement.
# echo 1 > /sys/module/rcutree/parameters/rcu_normal_wake_from_gp
After setting,
# time ppc64_cpu --smt=1;
real 1m10.726s # Run 1
real 1m12.530s # Run 2
# time ppc64_cpu --smt=8
real 0m36.661s # Run 1
real 0m41.401s # Run 2
Regards,
vishalc
