These patches introduce uniprocessor or CPU<->device equivalents for
smp_load_acquire() and smp_store_release(). These two new primitives are:
load_acquire()
store_release()
The first patch adds the primitives for the applicable architectures and
asm-generic.
The second patch adds the primitives to r8169 which turns out to be a good
example of where the new primitives might be useful as they have memory
barriers ordering accesses to the descriptors and the DescOwn bit within the
descriptors which follow acquire/release style semantics.
The third patch adds support for load_acquire() to the Intel fm10k, igb,
and ixgbe drivers. Testing with the ixgbe driver has shown a processing
time reduction of at least 7ns per 64B frame on a Core i7-4930K.
This patch series is essentially the v2 for:
arch: Introduce read_acquire()
The key changes in this patch series versus that patch are:
- Renamed read_acquire() to be consistent with smp_load_acquire()
- Changed barrier used to be consistent with smp_load_acquire()
- Updated PowerPC code to use __lwsync based on IBM article
- Added store_release() as this is a viable use case for drivers
- Added r8169 patch which is able to fully use primitives
- Added fm10k/igb/ixgbe patch which is able to test performance
---
Alexander Duyck (3):
arch: Introduce load_acquire() and store_release()
r8169: Use load_acquire() and store_release() to reduce memory barrier overhead
fm10k/igb/ixgbe: Use load_acquire on Rx descriptor
arch/arm/include/asm/barrier.h | 15 ++++++
arch/arm64/include/asm/barrier.h | 59 +++++++++++++------------
arch/ia64/include/asm/barrier.h | 7 ++-
arch/metag/include/asm/barrier.h | 15 ++++++
arch/mips/include/asm/barrier.h | 15 ++++++
arch/powerpc/include/asm/barrier.h | 24 ++++++++--
arch/s390/include/asm/barrier.h | 7 ++-
arch/sparc/include/asm/barrier_64.h | 6 ++-
arch/x86/include/asm/barrier.h | 22 ++++++++-
drivers/net/ethernet/intel/fm10k/fm10k_main.c | 8 +--
drivers/net/ethernet/intel/igb/igb_main.c | 8 +--
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 11 ++---
drivers/net/ethernet/realtek/r8169.c | 23 ++++------
include/asm-generic/barrier.h | 15 ++++++
14 files changed, 163 insertions(+), 72 deletions(-)
--
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