> From: Thomas Monjalon [mailto:tho...@monjalon.net] > Sent: Monday, 31 July 2023 14.14 > > Hello, > > What's the status of this feature?
I haven't given up on upstreaming this feature, but there doesn't seem to be much demand for it, so working on it has low priority. > > > 10/10/2022 08:46, Morten Brørup: > > This patch provides a function for memory copy using non-temporal store, > > load or both, controlled by flags passed to the function. > > > > Applications sometimes copy data to another memory location, which is only > > used much later. > > In this case, it is inefficient to pollute the data cache with the copied > > data. > > > > An example use case (originating from a real life application): > > Copying filtered packets, or the first part of them, into a capture buffer > > for offline analysis. > > > > The purpose of the function is to achieve a performance gain by not > > polluting the cache when copying data. > > Although the throughput can be improved by further optimization, I do not > > have time to do it now. > > > > The functional tests and performance tests for memory copy have been > > expanded to include non-temporal copying. > > > > A non-temporal version of the mbuf library's function to create a full > > copy of a given packet mbuf is provided. > > > > The packet capture and packet dump libraries have been updated to use > > non-temporal memory copy of the packets. > > > > Implementation notes: > > > > Implementations for non-x86 architectures can be provided by anyone at a > > later time. I am not going to do it. > > > > x86 non-temporal load instructions must be 16 byte aligned [1], and > > non-temporal store instructions must be 4, 8 or 16 byte aligned [2]. > > > > ARM non-temporal load and store instructions seem to require 4 byte > > alignment [3]. > > > > [1] https://www.intel.com/content/www/us/en/docs/intrinsics-guide/ > > index.html#text=_mm_stream_load > > [2] https://www.intel.com/content/www/us/en/docs/intrinsics-guide/ > > index.html#text=_mm_stream_si > > [3] https://developer.arm.com/documentation/100076/0100/ > > A64-Instruction-Set-Reference/A64-Floating-point-Instructions/ > > LDNP--SIMD-and-FP- > > > > This patch is a major rewrite from the RFC v3, so no version log comparing > > to the RFC is provided. > > > > v4 > > * Also ignore the warning for clang int the workaround for > > _mm_stream_load_si128() missing const in the parameter. > > * Add missing C linkage specifier in rte_memcpy.h. > > > > v3 > > * _mm_stream_si64() is not supported on 32-bit x86 architecture, so only > > use it on 64-bit x86 architecture. > > * CLANG warns that _mm_stream_load_si128_const() and > > rte_memcpy_nt_15_or_less_s16a() are not public, > > so remove __rte_internal from them. It also affects the documentation > > for the functions, so the fix can't be limited to CLANG. > > * Use __rte_experimental instead of __rte_internal. > > * Replace <n> with nnn in function documentation; it doesn't look like > > HTML. > > * Slightly modify the workaround for _mm_stream_load_si128() missing const > > in the parameter; the ancient GCC 4.5.8 in RHEL7 doesn't understand > > #pragma GCC diagnostic ignored "-Wdiscarded-qualifiers", so use > > #pragma GCC diagnostic ignored "-Wcast-qual" instead. I hope that works. > > * Fixed one coding style issue missed in v2. > > > > v2 > > * The last 16 byte block of data, incl. any trailing bytes, were not > > copied from the source memory area in rte_memcpy_nt_buf(). > > * Fix many coding style issues. > > * Add some missing header files. > > * Fix build time warning for non-x86 architectures by using a different > > method to mark the flags parameter unused. > > * CLANG doesn't understand RTE_BUILD_BUG_ON(!__builtin_constant_p(flags)), > > so omit it when using CLANG. > > > > Signed-off-by: Morten Brørup <m...@smartsharesystems.com> > > --- > > app/test/test_memcpy.c | 65 +- > > app/test/test_memcpy_perf.c | 187 ++-- > > lib/eal/include/generic/rte_memcpy.h | 127 +++ > > lib/eal/x86/include/rte_memcpy.h | 1238 ++++++++++++++++++++++++++ > > lib/mbuf/rte_mbuf.c | 77 ++ > > lib/mbuf/rte_mbuf.h | 32 + > > lib/mbuf/version.map | 1 + > > lib/pcapng/rte_pcapng.c | 3 +- > > lib/pdump/rte_pdump.c | 6 +- > > 9 files changed, 1645 insertions(+), 91 deletions(-) > > >
