Re: [PATCH v2 0/4] Optimise 64-bit IOVA allocations

[Ganapatrao Kulkarni <gklkml16-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On Wed, Aug 9, 2017 at 7:12 AM, Leizhen (ThunderTown)
<thunder.leizhen-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> wrote:
>
>
> On 2017/8/8 20:03, Ganapatrao Kulkarni wrote:
>> On Wed, Jul 26, 2017 at 4:47 PM, Leizhen (ThunderTown)
>> <thunder.leizhen-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> wrote:
>>>
>>>
>>> On 2017/7/26 19:08, Joerg Roedel wrote:
>>>> Hi Robin.
>>>>
>>>> On Fri, Jul 21, 2017 at 12:41:57PM +0100, Robin Murphy wrote:
>>>>> Hi all,
>>>>>
>>>>> In the wake of the ARM SMMU optimisation efforts, it seems that certain
>>>>> workloads (e.g. storage I/O with large scatterlists) probably remain quite
>>>>> heavily influenced by IOVA allocation performance. Separately, Ard also
>>>>> reported massive performance drops for a graphical desktop on AMD Seattle
>>>>> when enabling SMMUs via IORT, which we traced to dma_32bit_pfn in the DMA
>>>>> ops domain getting initialised differently for ACPI vs. DT, and exposing
>>>>> the overhead of the rbtree slow path. Whilst we could go around trying to
>>>>> close up all the little gaps that lead to hitting the slowest case, it
>>>>> seems a much better idea to simply make said slowest case a lot less slow.
>>>>
>>>> Do you have some numbers here? How big was the impact before these
>>>> patches and how is it with the patches?
>>> Here are some numbers:
>>>
>>> (before)$ iperf -s
>>> ------------------------------------------------------------
>>> Server listening on TCP port 5001
>>> TCP window size: 85.3 KByte (default)
>>> ------------------------------------------------------------
>>> [  4] local 192.168.1.106 port 5001 connected with 192.168.1.198 port 35898
>>> [ ID] Interval       Transfer     Bandwidth
>>> [  4]  0.0-10.2 sec  7.88 MBytes  6.48 Mbits/sec
>>> [  5] local 192.168.1.106 port 5001 connected with 192.168.1.198 port 35900
>>> [  5]  0.0-10.3 sec  7.88 MBytes  6.43 Mbits/sec
>>> [  4] local 192.168.1.106 port 5001 connected with 192.168.1.198 port 35902
>>> [  4]  0.0-10.3 sec  7.88 MBytes  6.43 Mbits/sec
>>>
>>> (after)$ iperf -s
>>> ------------------------------------------------------------
>>> Server listening on TCP port 5001
>>> TCP window size: 85.3 KByte (default)
>>> ------------------------------------------------------------
>>> [  4] local 192.168.1.106 port 5001 connected with 192.168.1.198 port 36330
>>> [ ID] Interval       Transfer     Bandwidth
>>> [  4]  0.0-10.0 sec  1.09 GBytes   933 Mbits/sec
>>> [  5] local 192.168.1.106 port 5001 connected with 192.168.1.198 port 36332
>>> [  5]  0.0-10.0 sec  1.10 GBytes   939 Mbits/sec
>>> [  4] local 192.168.1.106 port 5001 connected with 192.168.1.198 port 36334
>>> [  4]  0.0-10.0 sec  1.10 GBytes   938 Mbits/sec
>>>
>>
>> Is this testing done on Host or on Guest/VM?
> Host

As per your log, iperf throughput is improved to 938 Mbits/sec
from  6.43 Mbits/sec.
IMO, this seems to be unrealistic, some thing wrong with the testing?

>
>>
>>>>
>>>>
>>>>       Joerg
>>>>
>>>>
>>>> .
>>>>
>>>
>>> --
>>> Thanks!
>>> BestRegards
>>>
>>>
>>> _______________________________________________
>>> linux-arm-kernel mailing list
>>> linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>
>> thanks
>> Ganapat
>>
>> .
>>
>
> --
> Thanks!
> BestRegards
>

thanks
Ganapat