[dm-devel] [PATCH 0/2] Introduce the request handling for dm-crypt

[Baolin Wang]

On 13 November 2015 at 17:05, Arnd Bergmann <arnd at arndb.de> wrote:
> On Friday 13 November 2015 10:05:28 Baolin Wang wrote:
>>
>> Well, I did a simple test with dd reading, cause my engine limitation is 1M,
>> (1) so the time like below when handle 1M at one time.
>> 1048576 bytes (1.0 MB) copied, 0.0841235 s, 12.5 MB/s
>> 1048576 bytes (1.0 MB) copied, 0.0836294 s, 12.5 MB/s
>> 1048576 bytes (1.0 MB) copied, 0.0836526 s, 12.5 MB/s
>>
>> (2) These handle 64K at one time * 16 times
>> 1048576 bytes (1.0 MB) copied, 0.0937223 s, 11.2 MB/s
>> 1048576 bytes (1.0 MB) copied, 0.097205 s, 10.8 MB/s
>> 1048576 bytes (1.0 MB) copied, 0.0935884 s, 11.2 MB/s
>>
>> Here is a 10ms level difference, try to image if the hardware engine's
>> throughput is bigger than that. But like Jens said, we can measure it
>> by the performance data.
>
> The absolute numbers look really low. Does this include writing to
> a hard drive? That would certainly make the difference appear
> less significant.
>

OK, I'll supply the complete performance data to measure it.

> Could you try backing this with a ram disk backing for comparison,
> and also use 'time dd' to show the CPU utilization for all cases?
> For completeness, including cpu-only performance might also help
> put this into perspective.
>

OK, I'll try. Thanks.

>         Arnd



-- 
Baolin.wang
Best Regards