| Message ID | 20210718001423.6b8e1d23@xhacker (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | riscv: enable GENERIC_FIND_FIRST_BIT | expand |
Hi Palmer, On Sun, 18 Jul 2021 00:14:23 +0800 Jisheng Zhang wrote: > From: Jisheng Zhang <jszhang@kernel.org> > > riscv doesn't implement architecture-optimized bitsearching functions > such as find_first_{zero}_bit() etc. > > When GENERIC_FIND_FIRST_BIT=n, find_first_bit() is implemented with > find_next_bit() which is less efficient. Enable GENERIC_FIND_FIRST_BIT > for riscv to get more optimized find_first_bit() implementation, an > initial test(lib/find_bit_benchmark) shows find_first_bit() performance > is improved by nearly 32%. It seems this patch is missed. Is it possible to pick it up for 2nd 5.15-rc1 PR? Thanks > > Signed-off-by: Jisheng Zhang <jszhang@kernel.org> > --- > arch/riscv/Kconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index 8fcceb8eda07..7ebc54c5c245 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -47,6 +47,7 @@ config RISCV > select GENERIC_ATOMIC64 if !64BIT > select GENERIC_CLOCKEVENTS_BROADCAST if SMP > select GENERIC_EARLY_IOREMAP > + select GENERIC_FIND_FIRST_BIT > select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO > select GENERIC_IOREMAP > select GENERIC_IRQ_MULTI_HANDLER
On 2021/9/8 23:04, Jisheng Zhang wrote: > Hi Palmer, > > On Sun, 18 Jul 2021 00:14:23 +0800 > Jisheng Zhang wrote: > >> From: Jisheng Zhang <jszhang@kernel.org> >> >> riscv doesn't implement architecture-optimized bitsearching functions >> such as find_first_{zero}_bit() etc. >> >> When GENERIC_FIND_FIRST_BIT=n, find_first_bit() is implemented with >> find_next_bit() which is less efficient. Enable GENERIC_FIND_FIRST_BIT >> for riscv to get more optimized find_first_bit() implementation, an >> initial test(lib/find_bit_benchmark) shows find_first_bit() performance >> is improved by nearly 32%. > It seems this patch is missed. Is it possible to pick it up for 2nd 5.15-rc1 PR? > > Thanks It is enabled unconditionally by following commit commit dbbccfe505ef8fae804677abf0564c1e07479102 Author: Yury Norov <yury.norov@gmail.com> Date: Tue Aug 24 09:59:56 2021 +1000 arch: remove GENERIC_FIND_FIRST_BIT entirely > >> Signed-off-by: Jisheng Zhang <jszhang@kernel.org> >> --- >> arch/riscv/Kconfig | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig >> index 8fcceb8eda07..7ebc54c5c245 100644 >> --- a/arch/riscv/Kconfig >> +++ b/arch/riscv/Kconfig >> @@ -47,6 +47,7 @@ config RISCV >> select GENERIC_ATOMIC64 if !64BIT >> select GENERIC_CLOCKEVENTS_BROADCAST if SMP >> select GENERIC_EARLY_IOREMAP >> + select GENERIC_FIND_FIRST_BIT >> select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO >> select GENERIC_IOREMAP >> select GENERIC_IRQ_MULTI_HANDLER > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv > . >
On Thu, 9 Sep 2021 08:58:31 +0800 Kefeng Wang <wangkefeng.wang@huawei.com> wrote: > On 2021/9/8 23:04, Jisheng Zhang wrote: > > Hi Palmer, > > > > On Sun, 18 Jul 2021 00:14:23 +0800 > > Jisheng Zhang wrote: > > > >> From: Jisheng Zhang <jszhang@kernel.org> > >> > >> riscv doesn't implement architecture-optimized bitsearching functions > >> such as find_first_{zero}_bit() etc. > >> > >> When GENERIC_FIND_FIRST_BIT=n, find_first_bit() is implemented with > >> find_next_bit() which is less efficient. Enable GENERIC_FIND_FIRST_BIT > >> for riscv to get more optimized find_first_bit() implementation, an > >> initial test(lib/find_bit_benchmark) shows find_first_bit() performance > >> is improved by nearly 32%. > > It seems this patch is missed. Is it possible to pick it up for 2nd 5.15-rc1 PR? > > > > Thanks > > It is enabled unconditionally by following commit > > commit dbbccfe505ef8fae804677abf0564c1e07479102 > > Author: Yury Norov <yury.norov@gmail.com> > Date: Tue Aug 24 09:59:56 2021 +1000 > > arch: remove GENERIC_FIND_FIRST_BIT entirely > Aha, thanks for the information. After Yury's commit, this patch is useless now. thanks
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 8fcceb8eda07..7ebc54c5c245 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -47,6 +47,7 @@ config RISCV select GENERIC_ATOMIC64 if !64BIT select GENERIC_CLOCKEVENTS_BROADCAST if SMP select GENERIC_EARLY_IOREMAP + select GENERIC_FIND_FIRST_BIT select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO select GENERIC_IOREMAP select GENERIC_IRQ_MULTI_HANDLER