zfs/lib
Attila Fülöp 31b160f0a6
ICP: Improve AES-GCM performance
Currently SIMD accelerated AES-GCM performance is limited by two
factors:

a. The need to disable preemption and interrupts and save the FPU
state before using it and to do the reverse when done. Due to the
way the code is organized (see (b) below) we have to pay this price
twice for each 16 byte GCM block processed.

b. Most processing is done in C, operating on single GCM blocks.
The use of SIMD instructions is limited to the AES encryption of the
counter block (AES-NI) and the Galois multiplication (PCLMULQDQ).
This leads to the FPU not being fully utilized for crypto
operations.

To solve (a) we do crypto processing in larger chunks while owning
the FPU. An `icp_gcm_avx_chunk_size` module parameter was introduced
to make this chunk size tweakable. It defaults to 32 KiB. This step
alone roughly doubles performance. (b) is tackled by porting and
using the highly optimized openssl AES-GCM assembler routines, which
do all the processing (CTR, AES, GMULT) in a single routine. Both
steps together result in up to 32x reduction of the time spend in
the en/decryption routines, leading up to approximately 12x
throughput increase for large (128 KiB) blocks.

Lastly, this commit changes the default encryption algorithm from
AES-CCM to AES-GCM when setting the `encryption=on` property.

Reviewed-By: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-By: Jason King <jason.king@joyent.com>
Reviewed-By: Tom Caputi <tcaputi@datto.com>
Reviewed-By: Richard Laager <rlaager@wiktel.com>
Signed-off-by: Attila Fülöp <attila@fueloep.org>
Closes #9749
2020-02-10 12:59:50 -08:00
..
libavl OpenZFS restructuring - libspl 2019-10-02 10:39:48 -07:00
libefi cppcheck: (error) Memory leak: vtoc 2019-12-18 17:25:04 -08:00
libicp ICP: Improve AES-GCM performance 2020-02-10 12:59:50 -08:00
libnvpair Use correct format string when printing int8 2019-10-20 20:37:30 -07:00
libshare Fix static data to link with -fno-common 2020-02-06 09:25:29 -08:00
libspl ICP: Improve AES-GCM performance 2020-02-10 12:59:50 -08:00
libtpool OpenZFS restructuring - libspl 2019-10-02 10:39:48 -07:00
libunicode OpenZFS restructuring - libspl 2019-10-02 10:39:48 -07:00
libuutil Remove unused headers from uu_string.c 2019-10-25 13:53:50 -07:00
libzfs Disable get_numeric_property for xattr on FreeBSD 2020-01-21 15:06:10 -08:00
libzfs_core Add 'zfs send --saved' flag 2020-01-10 10:16:58 -08:00
libzpool async zvol minor node creation interferes with receive 2020-02-03 09:33:14 -08:00
libzutil Add wrapper stub for zfs_cmd ioctl to libzpool 2019-11-12 10:40:39 -08:00
Makefile.am Add libzutil for libzfs or libzpool consumers 2018-11-05 11:22:33 -08:00