Re: [PATCH 4/4] riscv: enable HAVE_FAST_GUP if MMU

[Alexandre Ghiti]

On 02/01/2024 04:25, Jisheng Zhang wrote:
> On Sun, Dec 31, 2023 at 07:37:33AM +0100, Alexandre Ghiti wrote:
> > On 19/12/2023 18:50, Jisheng Zhang wrote:
> > > Activate the fast gup for riscv mmu platforms. Here are some
> > > GUP_FAST_BENCHMARK performance numbers:
> > >
> > > Before the patch:
> > > GUP_FAST_BENCHMARK: Time: get:53203 put:5085 us
> > >
> > > After the patch:
> > > GUP_FAST_BENCHMARK: Time: get:17711 put:5060 us
> >
> > On which platform did you run this benchmark?
> T-HEAD th1520(cpufreq isn't enabled since the clk/pll isn't upstreamed,
> so cpu is running at the default freq set by u-boot)
> > > The get time is reduced by 66.7%! IOW, 3x get speed!
> >
> > Well done!
> >
> > Thanks,
> >
> > Alex
> >
> >
> > > Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxx>
> > > ---
> > >    arch/riscv/Kconfig               | 1 +
> > >    arch/riscv/include/asm/pgtable.h | 6 ++++++
> > >    2 files changed, 7 insertions(+)
> > >
> > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > > index d3555173d9f4..04df9920282d 100644
> > > --- a/arch/riscv/Kconfig
> > > +++ b/arch/riscv/Kconfig
> > > @@ -119,6 +119,7 @@ config RISCV
> > >    	select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
> > >    	select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION
> > >    	select HAVE_EBPF_JIT if MMU
> > > +	select HAVE_FAST_GUP if MMU
> > >    	select HAVE_FUNCTION_ARG_ACCESS_API
> > >    	select HAVE_FUNCTION_ERROR_INJECTION
> > >    	select HAVE_GCC_PLUGINS
> > > diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> > > index ab00235b018f..c6eb214139e6 100644
> > > --- a/arch/riscv/include/asm/pgtable.h
> > > +++ b/arch/riscv/include/asm/pgtable.h
> > > @@ -673,6 +673,12 @@ static inline int pmd_write(pmd_t pmd)
> > >    	return pte_write(pmd_pte(pmd));
> > >    }
> > > +#define pud_write pud_write
> > > +static inline int pud_write(pud_t pud)
> > > +{
> > > +	return pte_write(pud_pte(pud));
> > > +}
> > > +
> > >    static inline int pmd_dirty(pmd_t pmd)
> > >    {
> > >    	return pte_dirty(pmd_pte(pmd));


Thanks, you can add:

Reviewed-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>

Thanks,

Alex


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