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Maxime Méré
fb11a4f6af
Use DMA when buffer are aligned and with expected size. If buffer are correctly aligned and bigger than 1KB we have some performance gain: With DMA enable: $ openssl speed -evp aes-256-cbc -engine afalg -elapsed The 'numbers' are in 1000s of bytes per second processed. type 16 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes 16384 bytes aes-256-cbc 120.02k 406.78k 1588.82k 5873.32k 26020.52k 34258.94k Without DMA: $ openssl speed -evp aes-256-cbc -engine afalg -elapsed The 'numbers' are in 1000s of bytes per second processed. type 16 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes 16384 bytes aes-256-cbc 121.06k 419.95k 1112.23k 1897.47k 2362.03k 2386.60k With DMA: extract of $ modprobe tcrypt mode=500 testing speed of async cbc(aes) (stm32-cbc-aes) encryption tcrypt: test 14 (256 bit key, 16 byte blocks): 1 operation in 1679 cycles (16 bytes) tcrypt: test 15 (256 bit key, 64 byte blocks): 1 operation in 1893 cycles (64 bytes) tcrypt: test 16 (256 bit key, 128 byte blocks): 1 operation in 1760 cycles (128 bytes) tcrypt: test 17 (256 bit key, 256 byte blocks): 1 operation in 2154 cycles (256 bytes) tcrypt: test 18 (256 bit key, 1024 byte blocks): 1 operation in 2132 cycles (1024 bytes) tcrypt: test 19 (256 bit key, 1424 byte blocks): 1 operation in 2466 cycles (1424 bytes) tcrypt: test 20 (256 bit key, 4096 byte blocks): 1 operation in 4040 cycles (4096 bytes) Without DMA: $ modprobe tcrypt mode=500 tcrypt: test 14 (256 bit key, 16 byte blocks): 1 operation in 1671 cycles (16 bytes) tcrypt: test 15 (256 bit key, 64 byte blocks): 1 operation in 2263 cycles (64 bytes) tcrypt: test 16 (256 bit key, 128 byte blocks): 1 operation in 2881 cycles (128 bytes) tcrypt: test 17 (256 bit key, 256 byte blocks): 1 operation in 4270 cycles (256 bytes) tcrypt: test 18 (256 bit key, 1024 byte blocks): 1 operation in 11537 cycles (1024 bytes) tcrypt: test 19 (256 bit key, 1424 byte blocks): 1 operation in 15025 cycles (1424 bytes) tcrypt: test 20 (256 bit key, 4096 byte blocks): 1 operation in 40747 cycles (4096 bytes) Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com> Signed-off-by: Maxime Méré <maxime.mere@foss.st.com> Signed-off-by: Nicolas Toromanoff <nicolas.toromanoff@foss.st.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.