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

[Ganapatrao Kulkarni]

On Wed, Jul 26, 2017 at 4:47 PM, Leizhen (ThunderTown)
<thunder.leizhen at huawei.com> 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?

>>
>>
>>       Joerg
>>
>>
>> .
>>
>
> --
> Thanks!
> BestRegards
>
>
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thanks
Ganapat