On Wed, Jul 26, 2017 at 4:47 PM, Leizhen (ThunderTown)
[off-list ref] wrote:

On 2017/7/26 19:08, Joerg Roedel wrote:

quoted

Hi Robin.

On Fri, Jul 21, 2017 at 12:41:57PM +0100, Robin Murphy wrote:

quoted

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?

quoted

      Joerg


.

--
Thanks!
BestRegards


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thanks
Ganapat