Re: serpent-sse2 - different key size same speed?

[Jussi Kivilinna <jussi.kivilinna@xxxxxxxx>]

Quoting Zdenek Kaspar <zkaspar82@xxxxxxxxx>:

> Hello everyone,
>
> I just quick tested 3.3.0 kernel (x86_64) to get idea how serpent-sse2
> implementation works on Core2 machine. My dirty testing revealed that
> key size doesn't have impact on speed. Is such behavior normal ?

It's expected result, serpent speed does not depend on key-size and  
for example twofish and blowfish are another such ciphers where speed  
is key-size independent.

-Jussi

> Test machine: Core2 E6600 (2.40GHz), 3GB RAM, Scientific Linux 6.2
> dm-crypt on /dev/loop0, 1.5G image file:
> /dev/loop0: [0010]:11323 (/dev/shm/test.img)
>
>
> Encrypt (dd if=/dev/zero of=/dev/mapper/test bs=1M)
> -s 256 -c aes-xts-plain64     : 159 - 162 MB/s
> -s 512 -c aes-xts-plain64     : 129 - 141 MB/s
>
> -s 256 -c serpent-xts-plain64 : 142 - 146 MB/s
> -s 512 -c serpent-xts-plain64 : 139 - 148 MB/s
>
>
> Decrypt (dd if=/dev/mapper/test of=/dev/null bs=1M)
> -s 256 -c aes-xts-plain64     : 113 - 114 MB/s
> -s 512 -c aes-xts-plain64     :   90.1 MB/s
>
> -s 256 -c serpent-xts-plain64 :  105.0 MB/s
> -s 512 -c serpent-xts-plain64 :  105.0 MB/s
>
>
> (perf top shows as expected high usage of: serpent_dec_blk_8way and
> serpent_enc_blk_8way)
>
> Z.
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-crypto" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at  http://vger.kernel.org/majordomo-info.html



--
To unsubscribe from this list: send the line "unsubscribe linux-crypto" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html