Hi Daniel,
On 2017/2/9 18:11, Daniel P. Berrange wrote:
> On Thu, Feb 09, 2017 at 10:58:55AM +0800, Longpeng (Mike) wrote:
>> Hi Daniel,
>>
>> So...you prefer approach 1 with a driver-table dispatch layer, right?
>> And this implies that we must either rename some public methods in
>> cipher-gcrypt.c/cipher-nettle.c, or change them to 'static'.
>
> I'd suggest both - renaming them to have 'gcrypt' or 'nettle' in their
> name, and also make them static.
>
OK.
>> I also have some other ideas:
>>
>> 2) *maybe we need a heuristic policy*
>>
>> I added some speed test in test-crypto-cipher/hash and found that for big
>> packets AF_ALG is much faster than library-impl while library-impl is better
>> when the packets is small:
>>
>> packet(bytes) AF_ALG(MB/sec, intel QAT) Library-impl(MB/sec)
>> 512 53.68 127.82
>> 1024 98.39 133.21
>> 2048 167.56 134.62
>> 4096 276.21 135.10
>> 8192 410.80 135.82
>> 16384 545.08 136.01
>> 32768 654.49 136.30
>> 65536 723.00 136.29
>>
>> If a @alg is both supported by AF_ALG and library-impl, I think we should
>> decide
>> to use which one dynamically.
>
> What exactly are you measuring here?
>
> Is this comparing encryption of a fixed total size of data, and
> varying the packet size. ie sending 1024 * 512 byte packets against
> 256 * 2048 byte packages.
>
> Or is it sending a constant number of packets eg 1024 * 512 byte
> packets against 1024 * 2048 byte packets ?
>
The testcase encrypts data for 5 seconds and then calculates how many MBs it can
encrypt per second, as below:
g_test_timer_start();
do {
g_assert(qcrypto_cipher_setiv(cipher,
iv, niv,
&err) == 0);
g_assert(qcrypto_cipher_encrypt(cipher,
plaintext,
ciphertext,
chunk_size,
&err) == 0);
total += chunk_size;
} while (g_test_timer_elapsed() < 5.0);
total /= 1024 * 1024; /* to MB */
g_print("Testing cbc(aes128): ");
g_print("Encrypting in chunks of %ld bytes: ", chunk_size);
g_print("done. %.2f MB in %.2f secs: ", total, g_test_timer_last());
g_print("%.2f MB/sec\t", total / g_test_timer_last());
chunk_size = 512/1024/2048/.../65536 bytes.
Some other projects (ie. cryptodev-linux, libkcapi) also use this way to test
speed.
> The problem is that when constructing the cipher initially, we have no
> about the intended usage pattern, so can't decide which impl to use as
> is
>
Yep, I wanted to allocate both af_alg and library-impl objects and then we can
choose dynamically before, but now it seems too stupid. :)
Thanks.
>
> Regards,
> Daniel
--
Regards,
Longpeng(Mike)
