zfs/lib/libspl
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
..
asm-generic Unify target_cpu handling 2020-01-17 12:40:09 -08:00
asm-i386 Fix atomic_sub_64() i386 assembly implementation 2017-02-01 09:36:47 -08:00
asm-x86_64 Make asm-x86_64/atomic.S build on FreeBSD 2019-11-30 15:42:00 -08:00
include ICP: Improve AES-GCM performance 2020-02-10 12:59:50 -08:00
os/linux OpenZFS restructuring - libspl 2019-10-02 10:39:48 -07:00
Makefile.am Unify target_cpu handling 2020-01-17 12:40:09 -08:00
list.c Add linux libspl support 2010-08-31 13:41:59 -07:00
mkdirp.c Fix typos in lib/ 2019-09-02 17:53:27 -07:00
page.c ABD optimized page allocation code 2016-11-29 14:34:33 -08:00
strlcat.c Check for strlcat and strlcpy 2018-12-11 16:01:41 -08:00
strlcpy.c Check for strlcat and strlcpy 2018-12-11 16:01:41 -08:00
timestamp.c Fix `zpool iostat -T d 1` on musl 2017-04-12 08:57:46 -07:00
zone.c libspl: declare aok extern in header 2019-12-26 10:52:14 -08:00