Nick Terrell b1a3e75e46 lz4: fix kernel decompression speed ... This patch replaces all memcpy() calls with LZ4_memcpy() which calls __builtin_memcpy() so the compiler can inline it. LZ4 relies heavily on memcpy() with a constant size being inlined. In x86 and i386 pre-boot environments memcpy() cannot be inlined because memcpy() doesn't get defined as __builtin_memcpy(). An equivalent patch has been applied upstream so that the next import won't lose this change [1]. I've measured the kernel decompression speed using QEMU before and after this patch for the x86_64 and i386 architectures. The speed-up is about 10x as shown below. Code Arch Kernel Size Time Speed v5.8 x86_64 11504832 B 148 ms 79 MB/s patch x86_64 11503872 B 13 ms 885 MB/s v5.8 i386 9621216 B 91 ms 106 MB/s patch i386 9620224 B 10 ms 962 MB/s I also measured the time to decompress the initramfs on x86_64, i386, and arm. All three show the same decompression speed before and after, as expected. [1] https://github.com/lz4/lz4/pull/890 Signed-off-by: Nick Terrell <terrelln@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Yann Collet <yann.collet.73@gmail.com> Cc: Gao Xiang <gaoxiang25@huawei.com> Cc: Sven Schmidt <4sschmid@informatik.uni-hamburg.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Link: http://lkml.kernel.org/r/20200803194022.2966806-1-nickrterrell@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2020-08-14 19:56:56 -07:00
..
lz4_compress.c
lz4_decompress.c
lz4defs.h
lz4hc_compress.c
Makefile