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

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Date:   Wed, 9 Aug 2017 09:42:15 +0800
From:   "Leizhen (ThunderTown)" <thunder.leizhen@...wei.com>
To:     Ganapatrao Kulkarni <gklkml16@...il.com>
CC:     Joerg Roedel <joro@...tes.org>,
        Robin Murphy <robin.murphy@....com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        <ard.biesheuvel@...aro.org>, <linux-kernel@...r.kernel.org>,
        <iommu@...ts.linux-foundation.org>, <ray.jui@...adcom.com>,
        <nwatters@...eaurora.org>, <Jonathan.Cameron@...wei.com>,
        <dwmw2@...radead.org>, <linux-arm-kernel@...ts.infradead.org>,
        Ganapatrao Kulkarni <ganapatrao.kulkarni@...ium.com>
Subject: Re: [PATCH v2 0/4] Optimise 64-bit IOVA allocations


On 2017/8/8 20:03, Ganapatrao Kulkarni wrote:
> On Wed, Jul 26, 2017 at 4:47 PM, Leizhen (ThunderTown)
> <thunder.leizhen@...wei.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?
Host

> 
>>>
>>>
>>>       Joerg
>>>
>>>
>>> .
>>>
>>
>> --
>> Thanks!
>> BestRegards
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@...ts.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 
> thanks
> Ganapat
> 
> .
> 

-- 
Thanks!
BestRegards

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