Re: Qualcomm Crypto Engine performance numbers on mainline kernel

[Christian Lamparter <chunkeey@gmail.com>]

On 05/06/2021 17:32, Ard Biesheuvel wrote:
> Hello Thara,
> 
> On Fri, 4 Jun 2021 at 18:49, Thara Gopinath <thara.gopinath@linaro.org> wrote:
>>
>>
>> Hi All,
>>
>> Below are the performance numbers from running "crypsetup benchmark" on
>> CE algorithms in the mainline kernel. All numbers are in MiB/s. The
>> platform used is RB3 for sdm845 and MTPs for rest of them.
>>
>>
>>                          SDM845    SM8150     SM8250     SM8350
>> AES-CBC (128)
>> Encrypt / Decrypt       114/106  36/48       120/188    133/197
>>
>> AES-XTS (256)
>> Encrypt / Decrypt       100/102  49/48       186/187    n/a
>>
> 
> The CPU instruction based ones are apparently an order of magnitude
> faster, and are synchronous so their latency should be lower.
> 
> So, as Eric already pointed out IIRC, there doesn't seem to be much
> value in enabling this IP in Linux - it should not be the default
> choice/highest priority, and it is not obvious to me whether/when you
> would prefer this implementation over the CPU based one. Do you have
> any idea how many queues it has, or how much data it can process in
> parallel? Are there other features that stand out?

While I can't say much for the qce-crypto. I do know that "cryptsetup
benchmark" isn't the greatest for pitting the hardware accelerated
crypto against the CPU in some instances.

In my case (crypto4xx / CPU is a PowerPC 464 800MHz - Hardware is a
Western Digital My Book Live - NAS) the "benchmark" results look
exceptionally poor:
#     Algorithm |       Key |      Encryption |      Decryption
         aes-cbc        128b         8.0 MiB/s         8.7 MiB/s
         aes-cbc        256b         8.7 MiB/s         8.7 MiB/s
         aes-xts        256b         5.3 MiB/s         7.9 MiB/s
         aes-xts        512b         7.9 MiB/s         7.9 MiB/s
(Hardware doesn't have cts/xts, but aes-cbc, aes-ctr and aes-gcm)

(for comparison, these are numbers that are produced by only the
800 MHz PowerPC CPU)
         aes-cbc        128b        15.8 MiB/s        16.3 MiB/s
         aes-cbc        256b        12.3 MiB/s        12.8 MiB/s
         aes-xts        256b        12.5 MiB/s        15.1 MiB/s
         aes-xts        512b        11.9 MiB/s        12.0 MiB/s


and (openssl speed -evp aes-128-cbc --elapsed -seconds 3) software
manages similar numbers:

type             16 bytes     64 bytes    256 bytes   1024 bytes   8192 bytes  16384 bytes
aes-128-cbc      12646.42k    16806.66k    18349.31k    18762.07k    18896.21k    18879.83k

However, when I format a partition on the NAS HDD with
cryptsetup + crypto4xx and use hdparm -i / dd

# hdparm -t /dev/mapper/aes-cbc-hw-test

/dev/mapper/aes-cbc-hw-test:
  Timing buffered disk reads:  96 MB in  3.05 seconds =  31.46 MB/sec

# dd if=/dev/mapper/aes-cbc-hw-test of=/dev/null bs=8M status=progress
5318377472 bytes (5.3 GB, 5.0 GiB) copied, 143 s, 37.2 MB/s^C
639+0 records in
638+0 records out
5351931904 bytes (5.4 GB, 5.0 GiB) copied, 144.246 s, 37.1 MB/s

whereas without crypto4xx:

# hdparm -t /dev/mapper/aes-cbc-hw-test

/dev/mapper/aes-cbc-hw-test:
  Timing buffered disk reads:  34 MB in  3.14 seconds =  10.82 MB/sec

# dd if=/dev/mapper/aes-cbc-hw-test of=/dev/null bs=8M status=progress
46+0 records in
45+0 records out
377487360 bytes (377 MB, 360 MiB) copied, 33.1952 s, 11.4 MB/s

This is 2-3 times the throughput that the CPU alone could do.

@Thara, Do you have a usb-3.0 + fast 3.0 usb-stick? If so, try
to format a partition on it for cryptsetup and try it there.

Cheers,
Christian