Hi Pavan,
> -----Original Message----- > From: Pavan Nikhilesh Bhagavatula <[email protected]> > Sent: Monday, July 1, 2019 5:59 PM > To: Gavin Hu (Arm Technology China) <[email protected]>; [email protected] > Cc: [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; Honnappa > Nagarahalli <[email protected]>; nd <[email protected]> > Subject: RE: [dpdk-dev] [RFC 1/5] eal: add the APIs to wait until equal > > Hi Gavin, > > >-----Original Message----- > >From: dev <[email protected]> On Behalf Of Gavin Hu > >Sent: Sunday, June 30, 2019 9:51 PM > >To: [email protected] > >Cc: [email protected]; Jerin Jacob Kollanukkaran > ><[email protected]>; [email protected]; > >[email protected]; [email protected]; > >[email protected]; [email protected]; [email protected] > >Subject: [dpdk-dev] [RFC 1/5] eal: add the APIs to wait until equal > > > >The rte_wait_until_equal_xxx APIs abstract the functionality of 'polling > >for a memory location to become equal to a given value'. > > > >Signed-off-by: Gavin Hu <[email protected]> > >Reviewed-by: Ruifeng Wang <[email protected]> > >Reviewed-by: Steve Capper <[email protected]> > >Reviewed-by: Ola Liljedahl <[email protected]> > >Reviewed-by: Honnappa Nagarahalli <[email protected]> > >--- > > .../common/include/arch/arm/rte_pause_64.h | 143 > >+++++++++++++++++++++ > > lib/librte_eal/common/include/generic/rte_pause.h | 20 +++ > > 2 files changed, 163 insertions(+) > > > >diff --git a/lib/librte_eal/common/include/arch/arm/rte_pause_64.h > >b/lib/librte_eal/common/include/arch/arm/rte_pause_64.h > >index 93895d3..0095da6 100644 > >--- a/lib/librte_eal/common/include/arch/arm/rte_pause_64.h > >+++ b/lib/librte_eal/common/include/arch/arm/rte_pause_64.h > >@@ -17,6 +17,149 @@ static inline void rte_pause(void) > > asm volatile("yield" ::: "memory"); > > } > > > >+#ifdef RTE_USE_WFE > >+#define rte_wait_until_equal_relaxed(addr, expected) do {\ > >+ typeof(*addr) tmp; \ > >+ if (__builtin_constant_p((expected))) \ > >+ do { \ > >+ if (sizeof(*(addr)) == 16)\ > >+ asm volatile( \ > >+ "sevl\n" \ > >+ "1: wfe\n" \ > >+ "ldxrh %w0, %1\n" \ > >+ "cmp %w0, %w2\n" \ > >+ "bne 1b\n" \ > >+ : "=&r"(tmp) \ > >+ : "Q"(*addr), > >"i"(expected) \ > >+ : "cc", "memory"); \ > > Can we have early exit here i.e. instead of going directly to wfe can we first > check the condition and then fallthrough? > Something like: > asm volatile(" ldxrh %w0 %1 \n" > " cmp %w0 %w2 \n" > " b.eq 2: \n" > "1: wfe \n" > " ldxrh %w0, %1 \n" > " cmp %w0, %w2 \n" > " b.ne 1b \n" > "2: \n" > :::); > > Regards, > Pavan. Ok, I will do it in next version.
