[PATCH v2 0/2] riscv: enable lockless lockref implementation
Jisheng Zhang
jszhang at kernel.org
Sat Dec 2 06:03:21 PST 2023
This series selects ARCH_USE_CMPXCHG_LOCKREF to enable the
cmpxchg-based lockless lockref implementation for riscv. Then,
implement arch_cmpxchg64_{relaxed|acquire|release}.
After patch1:
Using Linus' test case[1] on TH1520 platform, I see a 11.2% improvement.
On JH7110 platform, I see 12.0% improvement.
After patch2:
on both TH1520 and JH7110 platforms, I didn't see obvious
performance improvement with Linus' test case [1]. IMHO, this may
be related with the fence and lr.d/sc.d hw implementations. In theory,
lr/sc without fence could give performance improvement over lr/sc plus
fence, so add the code here to leave performance improvement room on
newer HW platforms.
Link: http://marc.info/?l=linux-fsdevel&m=137782380714721&w=4 [1]
Since v1:
- only select ARCH_USE_CMPXCHG_LOCKREF if 64BIT
Jisheng Zhang (2):
riscv: select ARCH_USE_CMPXCHG_LOCKREF
riscv: cmpxchg: implement arch_cmpxchg64_{relaxed|acquire|release}
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/cmpxchg.h | 18 ++++++++++++++++++
2 files changed, 19 insertions(+)
--
2.42.0
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