From: Nicholas Piggin <npiggin@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-arch@vger.kernel.org, Rik van Riel <riel@redhat.com>,
Will Deacon <will@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
linuxppc-dev@lists.ozlabs.org,
Nicholas Piggin <npiggin@gmail.com>,
linux-mm@kvack.org, Andy Lutomirski <luto@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Nadav Amit <nadav.amit@gmail.com>
Subject: [PATCH v7 5/5] powerpc/64s: enable MMU_LAZY_TLB_SHOOTDOWN
Date: Fri, 3 Feb 2023 17:18:37 +1000 [thread overview]
Message-ID: <20230203071837.1136453-6-npiggin@gmail.com> (raw)
In-Reply-To: <20230203071837.1136453-1-npiggin@gmail.com>
On a 16-socket 192-core POWER8 system, the context_switch1_threads
benchmark from will-it-scale (see earlier changelog), upstream can
achieve a rate of about 1 million context switches per second, due to
contention on the mm refcount.
64s meets the prerequisites for CONFIG_MMU_LAZY_TLB_SHOOTDOWN, so enable
the option. This increases the above benchmark to 118 million context
switches per second.
This generates 314 additional IPI interrupts on a 144 CPU system doing
a kernel compile, which is in the noise in terms of kernel cycles.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index b8c4ac56bddc..600ace5a7f1a 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -265,6 +265,7 @@ config PPC
select MMU_GATHER_PAGE_SIZE
select MMU_GATHER_RCU_TABLE_FREE
select MMU_GATHER_MERGE_VMAS
+ select MMU_LAZY_TLB_SHOOTDOWN if PPC_BOOK3S_64
select MODULES_USE_ELF_RELA
select NEED_DMA_MAP_STATE if PPC64 || NOT_COHERENT_CACHE
select NEED_PER_CPU_EMBED_FIRST_CHUNK if PPC64
--
2.37.2
next prev parent reply other threads:[~2023-02-03 7:24 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-03 7:18 [PATCH v7 0/5] shoot lazy tlbs (lazy tlb refcount scalability improvement) Nicholas Piggin
2023-02-03 7:18 ` [PATCH v7 1/5] kthread: simplify kthread_use_mm refcounting Nicholas Piggin
2023-02-03 7:18 ` [PATCH v7 2/5] lazy tlb: introduce lazy tlb mm refcount helper functions Nicholas Piggin
2023-02-03 7:18 ` [PATCH v7 3/5] lazy tlb: allow lazy tlb mm refcounting to be configurable Nicholas Piggin
2023-02-03 7:18 ` [PATCH v7 4/5] lazy tlb: shoot lazies, non-refcounting lazy tlb mm reference handling scheme Nicholas Piggin
2023-02-03 7:18 ` Nicholas Piggin [this message]
2023-02-26 22:12 ` [PATCH v7 5/5] powerpc/64s: enable MMU_LAZY_TLB_SHOOTDOWN Andrew Morton
2023-02-27 13:33 ` Peter Zijlstra
2023-03-21 3:54 ` Nicholas Piggin
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