Hi Milan,
Milan Broz <gmazyland@xxxxxxxxx> writes:
> So 2 * performance increase? I would expect even more...
> (Maybe compare it with new cryptsetup benchmark - in fact it uses much
> larger block and it should measure almost real throughput or crypto
> engine.)
In cryptsetup benchmark I am seeing much higher numbers, but I never get
close to that in “real” tests:
# Tests are approximate using memory only (no storage IO).
PBKDF2-sha1 44887 iterations per second
PBKDF2-sha256 34492 iterations per second
PBKDF2-sha512 8904 iterations per second
PBKDF2-ripemd160 43115 iterations per second
PBKDF2-whirlpool 6884 iterations per second
# Algorithm | Key | Encryption | Decryption
aes-cbc 128b 254.0 MiB/s 264.0 MiB/s
serpent-cbc 128b 17.5 MiB/s 17.8 MiB/s
twofish-cbc 128b 20.4 MiB/s 20.6 MiB/s
aes-cbc 256b 245.0 MiB/s 242.0 MiB/s
serpent-cbc 256b 17.5 MiB/s 18.0 MiB/s
twofish-cbc 256b 20.4 MiB/s 20.8 MiB/s
aes-xts 256b 21.6 MiB/s 21.8 MiB/s
serpent-xts 256b 18.0 MiB/s 18.0 MiB/s
twofish-xts 256b 21.0 MiB/s 20.6 MiB/s
aes-xts 512b 17.0 MiB/s 17.1 MiB/s
serpent-xts 512b 18.0 MiB/s 18.0 MiB/s
twofish-xts 512b 21.0 MiB/s 20.6 MiB/s
> This looks like crash in different layer, IMHO this should happen even
> with other devices (try dm-linear). If it is reproducible, perhaps
> report it to LKML.
How would I be able to reproduce this with dm-linear? As far as I can
tell, it doesn’t have a block size parameter?
Apparently, using a block size bigger than PAGESIZE is not possible with
Linux currently. Ted Ts'o writes that he is surprised to see the
patchset to allow that being used in the wild:
https://lkml.org/lkml/2012/3/21/493
I have compared dm-linear with the dm-crypt null cipher:
echo "0 5856626815 linear /dev/sda2 0" | dmsetup create identity
dd if=/dev/zero of=/dev/mapper/identity bs=1M count=768 oflag=direct conv=fsync
768+0 records in
768+0 records out
805306368 bytes (805 MB) copied, 4.69666 s, 171 MB/s
cryptsetup luksFormat -c null /dev/sda2
cryptsetup luksOpen /dev/sda2 sda2_crypt
dd if=/dev/zero of=/dev/mapper/sda2_crypt bs=1M count=768 oflag=direct conv=fsync
768+0 records in
768+0 records out
805306368 bytes (805 MB) copied, 9.39298 s, 85.7 MB/s
This is quite a difference and I wonder what might cause it.
Here is the same test with 4096 bytes big blocks:
echo "0 5856624640 crypt cipher_null-ecb - 0 /dev/sda2 0 2 block_size 4096" | dmsetup create sda2_crypt
dd if=/dev/zero of=/dev/mapper/sda2_crypt bs=1M count=768 oflag=direct conv=fsync
768+0 records in
768+0 records out
805306368 bytes (805 MB) copied, 6.25626 s, 129 MB/s
So, any ideas on how to further debug where the problem is, or how we
can get to approximately 170 MB/s? :-)
--
Best regards,
Michael
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