[PATCH 0/2] eal/riscv: implement prefetch using zicbop

[Daniel Gregory]

Instructions from RISC-V's Zicbop extension can be used to implement the
rte_prefetch* family of functions. On modern versions of GCC (13.1.0+)
and Clang (17.0.1+), these are emitted by __builtin_prefetch() when the
extension is present.

In order to support older compiler versions, this patchset manually
emits these instructions using inline assembly. To do this, I have added
a new flag, RTE_PREFETCH_WRITE_ARCH_DEFINED, that
(similarly to RTE_WAIT_UNTIL_EQUAL_ARCH_DEFINED) hides the generic
implementation of rte_prefetch*_write.

I am still in the process of acquiring hardware that supports this
extension, so I haven't tested how this affects performance yet.

Daniel Gregory (2):
  eal: add flag to hide generic prefetch_write
  eal/riscv: add support for zicbop extension

 config/riscv/meson.build               |  6 +++
 lib/eal/include/generic/rte_prefetch.h | 47 +++++++++++++--------
 lib/eal/riscv/include/rte_prefetch.h   | 57 ++++++++++++++++++++++++--
 3 files changed, 90 insertions(+), 20 deletions(-)

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2.39.2