On Fri, Jan 26, 2018 at 01:54:23PM -0800, Stephen Hemminger wrote: > On Fri, 26 Jan 2018 17:24:40 +0000 > Bruce Richardson <bruce.richard...@intel.com> wrote: > > > On Fri, Jan 26, 2018 at 06:14:01PM +0100, Thomas Monjalon wrote: > > > 26/01/2018 03:01, Stephen Hemminger: > > > > To handle atomic update of link status (64 bit), every driver was > > > > doing its own version using cmpset. Atomic exchange is a useful > > > > primitive in its own right; therefore make it a EAL routine. > > > > > > > > Signed-off-by: Stephen Hemminger <step...@networkplumber.org> --- > > > > .../common/include/arch/ppc_64/rte_atomic.h | 21 +++++- > > > > .../common/include/arch/x86/rte_atomic.h | 24 +++++++ > > > > .../common/include/arch/x86/rte_atomic_32.h | 12 ++++ > > > > .../common/include/arch/x86/rte_atomic_64.h | 12 ++++ > > > > lib/librte_eal/common/include/generic/rte_atomic.h | 78 > > > > ++++++++++++++++++++++ 5 files changed, 146 insertions(+), 1 > > > > deletion(-) > > > > > > Looks good, thanks. > > > > > > It probably deserves a review by PPC experts. Adding Chao, maintainer > > > of this part. + Bruce and Konstantin for x86 part. > > > > > Would it not be simpler to use __sync_bool_compare_and_swap compiler > > built-in on all supported platforms? Do we really need the per-platform > > optimization of this? > > > > /Bruce > > Exchange is different than compare and swap. The is nice atomic intrinsic > in GCC. The x86 part is in Linux and BSD already.
Yes, sorry, I picked the wrong builtin. I should have referenced instead "__sync_lock_test_and_set", which is an xchg op according to the docs [https://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/Atomic-Builtins.html].
