Messages in this thread Patch in this message | | | Date | Mon, 29 Aug 2022 22:10:53 +0800 | From | Jisheng Zhang <> | Subject | Re: [PATCH v2] riscv: enable THP_SWAP for RV64 |
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On Sat, Aug 27, 2022 at 09:13:03PM +0000, Conor.Dooley@microchip.com wrote: > Hey Jisheng,
Hi Conor,
> On 27/08/2022 10:58, Jisheng Zhang wrote: > > I have a Sipeed Lichee RV dock board which only has 512MB DDR, so > > memory optimizations such as swap on zram are helpful. As is seen > > in commit d0637c505f8a ("arm64: enable THP_SWAP for arm64") and > > commit bd4c82c22c367e ("mm, THP, swap: delay splitting THP after > > swapped out"), THP_SWAP can improve the swap throughput significantly. > > > > Enable THP_SWAP for RV64, testing the micro-benchmark which is > > introduced by commit d0637c505f8a ("arm64: enable THP_SWAP for arm64") > > shows below numbers on the Lichee RV dock board: > > > > thp swp throughput w/o patch: 66908 bytes/ms (mean of 10 tests) > > thp swp throughput w/ patch: 322638 bytes/ms (mean of 10 tests) > > I know the original commit message contains this, but it's a little > odd. If the patch /enables/ THP then how would there be THP swap > prior to the patch?
hmm, it's swap I'll send a v3 to correct the description.
> > > > > Improved by 382%! > > I could not replicate the after numbers on my nezha, so I suspect > I am missing something in my config/setup. zswap is enabled and is
swap on zram rather than zswap ;)
> working, TRANSPARENT_HUGEPAGE is enabled etc. Not that it matters > for acceptance of the patch though. > > I gave it a try and nothing went up in flames while using zswap so: > Reviewed-by: Conor Dooley <conor.dooley@microchip.com> > > > > > Signed-off-by: Jisheng Zhang <jszhang@kernel.org> > > Reviewed-by: Andrew Jones <ajones@ventanamicro.com> > > --- > > Since v1: > > - collect reviewed-by tag > > - make ARCH_WANTS_THP_SWAP rely on HAVE_ARCH_TRANSPARENT_HUGEPAGE > > instead > > > > arch/riscv/Kconfig | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > > index ed66c31e4655..79e52441e18b 100644 > > --- a/arch/riscv/Kconfig > > +++ b/arch/riscv/Kconfig > > @@ -45,6 +45,7 @@ config RISCV > > select ARCH_WANT_FRAME_POINTERS > > select ARCH_WANT_GENERAL_HUGETLB > > select ARCH_WANT_HUGE_PMD_SHARE if 64BIT > > + select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE > > select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU > > select BUILDTIME_TABLE_SORT if MMU > > select CLONE_BACKWARDS
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