On Tue, Oct 01, 2024 at 09:02:01PM -0400, Mathieu Desnoyers wrote:
> Hazard pointers appear to be a good fit for replacing refcount based lazy
> active mm tracking.
>
> Highlight:
>
> will-it-scale context_switch1_threads
>
> nr threads (-t) speedup
> 24 +3%
> 48 +12%
> 96 +21%
> 192 +28%
Impressive!!!
I have to ask... Any data for smaller numbers of CPUs?
Thanx, Paul
> I'm curious to see what the build bots have to say about this.
>
> This series applies on top of v6.11.1.
>
> Signed-off-by: Mathieu Desnoyers <[email protected]>
> Cc: Nicholas Piggin <[email protected]>
> Cc: Michael Ellerman <[email protected]>
> Cc: Greg Kroah-Hartman <[email protected]>
> Cc: Sebastian Andrzej Siewior <[email protected]>
> Cc: "Paul E. McKenney" <[email protected]>
> Cc: Will Deacon <[email protected]>
> Cc: Boqun Feng <[email protected]>
> Cc: Alan Stern <[email protected]>
> Cc: John Stultz <[email protected]>
> Cc: Neeraj Upadhyay <[email protected]>
> Cc: Boqun Feng <[email protected]>
> Cc: Frederic Weisbecker <[email protected]>
> Cc: Joel Fernandes <[email protected]>
> Cc: Josh Triplett <[email protected]>
> Cc: Uladzislau Rezki <[email protected]>
> Cc: Steven Rostedt <[email protected]>
> Cc: Lai Jiangshan <[email protected]>
> Cc: Zqiang <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Waiman Long <[email protected]>
> Cc: Mark Rutland <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Vlastimil Babka <[email protected]>
> Cc: [email protected]
> Cc: Mateusz Guzik <[email protected]>
> Cc: Jonas Oberhauser <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
>
> Mathieu Desnoyers (4):
> compiler.h: Introduce ptr_eq() to preserve address dependency
> Documentation: RCU: Refer to ptr_eq()
> hp: Implement Hazard Pointers
> sched+mm: Use hazard pointers to track lazy active mm existence
>
> Documentation/RCU/rcu_dereference.rst | 38 ++++++-
> Documentation/mm/active_mm.rst | 9 +-
> arch/Kconfig | 32 ------
> arch/powerpc/Kconfig | 1 -
> arch/powerpc/mm/book3s64/radix_tlb.c | 23 +---
> include/linux/compiler.h | 63 +++++++++++
> include/linux/hp.h | 154 ++++++++++++++++++++++++++
> include/linux/mm_types.h | 3 -
> include/linux/sched/mm.h | 71 +++++-------
> kernel/Makefile | 2 +-
> kernel/exit.c | 4 +-
> kernel/fork.c | 47 ++------
> kernel/hp.c | 46 ++++++++
> kernel/sched/sched.h | 8 +-
> lib/Kconfig.debug | 10 --
> 15 files changed, 346 insertions(+), 165 deletions(-)
> create mode 100644 include/linux/hp.h
> create mode 100644 kernel/hp.c
>
> --
> 2.39.2
