Hi Jerin, Add the offlist discussion with Pavan to facilitate the review for the spinlock patch(currently in v6). Thanks Pavan and Jerin for review.
Best Regards, Gavin > -----Original Message----- > From: Gavin Hu (Arm Technology China) > Sent: Thursday, September 12, 2019 5:22 PM > To: Pavan Nikhilesh Bhagavatula <pbhagavat...@marvell.com> > Subject: RE: [EXT] [PATCH v4 5/6] spinlock: use wfe to reduce contention on > aarch64 > > Hi Pavan, > > Thanks for pointing this out, it was implemented in the API already. > Spinlock did not use the API to save a comparison branch(loading 0 to a reg > and compare against). > > Anyway it is also a good idea to add it into this asm code. > > Best Regards, > Gavin > > > -----Original Message----- > > From: Pavan Nikhilesh Bhagavatula <pbhagavat...@marvell.com> > > Sent: Thursday, September 12, 2019 4:45 PM > > To: Gavin Hu (Arm Technology China) <gavin...@arm.com> > > Subject: RE: [EXT] [PATCH v4 5/6] spinlock: use wfe to reduce contention on > > aarch64 > > > > Hi Gavin, (Offlist) > > > > I there a reason why the below asm doesn't use early exit as discussed in > > http://patches.dpdk.org/patch/55669/ > > > > Regards, > > Pavan. > > > > >+#ifndef RTE_FORCE_INTRINSICS > > >+static inline void > > >+rte_spinlock_lock(rte_spinlock_t *sl) > > >+{ > > >+ unsigned int tmp; > > >+ /* > > >http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc. > > >+ * faqs/ka16809.html > > >+ */ > > >+ asm volatile( > > >+ "sevl\n" > > >+ "1: wfe\n" > > >+ "2: ldaxr %w[tmp], %w[locked]\n" > > >+ "cbnz %w[tmp], 1b\n" > > >+ "stxr %w[tmp], %w[one], %w[locked]\n" > > >+ "cbnz %w[tmp], 2b\n" > > >+ : [tmp] "=&r" (tmp), [locked] "+Q"(sl->locked) > > >+ : [one] "r" (1) > > >+ : "cc", "memory"); > > >+} > > >+#endif > > >+ > > > static inline int rte_tm_supported(void) > > > { > > > return 0; > > >-- > > >2.7.4 IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
