Re: [RFC PATCH net-next v2 0/7] Improve GbEth performance on Renesas RZ/G2L and related SoCs
From: Sergey Shtylyov
Date: Mon Feb 12 2024 - 15:53:28 EST
On 2/12/24 2:52 PM, Paul Barker wrote:
[...]
>>> This series aims to improve peformance of the GbEth IP in the Renesas
>>
>> You didn't fix the typo in "peformance"... :-/
>>
>>> RZ/G2L SoC family and the RZ/G3S SoC, which use the ravb driver. Along
>>> the way, we do some refactoring and ensure that napi_complete_done() is
>>> used in accordance with the NAPI documentation for both GbEth and R-Car
>>> code paths.
>>>
>>> Performance improvment mainly comes from enabling SW IRQ Coalescing for
>>
>> And in "improvment" too... :-/
>
> I'll fix this and the above type in v3.
TIA! Chances are this will end up in the merge commit...
>>> all SoCs using the GbEth IP, and NAPI Threaded mode for single core SoCs
>>> using the GbEth IP. These can be enabled/disabled at runtime via sysfs,
>>> but our goal is to set sensible defaults which get good performance on
>>> the affected SoCs.
>>>
>>> The performance impact of this series on iperf3 testing is as follows:
>>> * RZ/G2L Ethernet throughput is unchanged, but CPU usage drops:
>>> * Bidirectional and TCP RX: 6.5% less CPU usage
>>> * UDP RX: 10% less CPU usage
>>>
>>> * RZ/G2UL and RZ/G3S Ethernet throughput is increased for all test
>>> cases except UDP TX, which suffers a slight loss:
>>> * TCP TX: 32% more throughput
>>> * TCP RX: 11% more throughput
>>> * UDP TX: 10% less throughput
>>> * UDP RX: 10183% more throughput - the previous throughput of
>>
>> So this is a real figure? I thought you forgot to erase 10... :-)
>
> Yes, throughput went from 1.06Mbps to 109Mbps for the RZ/G2UL with these
> changes.
Hm, that gives me even 10283%! :-)
> Initial testing shows that goes up again to 485Mbps with the next patch
> series I'm working on to reduce RX buffer sizes.
Oh, wow! :-)
> Biju's work on checksum offload also helps a lot with these numbers, I
> can't take all the credit.
Took 5 versions to merge, unfortunately... :-/
[...]
>>> Work in this area will continue, in particular we expect to improve
>>> TCP/UDP RX performance further with future changes to RX buffer
>>> handling.
>>>
>>> Changes v1->v2:
>>> * Marked as RFC as the series depends on unmerged patches.
>>> * Refactored R-Car code paths as well as GbEth code paths.
>>> * Updated references to the patches this series depends on.
>>>
>>> Paul Barker (7):
>>> net: ravb: Simplify poll & receive functions
>>
>> The below 3 commits fix issues in the GbEth code, so should
>> be redone against net.git and posted separately from this series...
>>
>>> net: ravb: Count packets instead of descriptors in RX path
>>> net: ravb: Always process TX descriptor ring
>>> net: ravb: Always update error counters
>
> I'll split out and re-submit these as bug fixes. "net: ravb: Count
> packets instead of descriptors in RX path" will require a bit of rework
> so it doesn't depend on the first patch of the series ("net: ravb:
> Simplify poll & receive functions") so you'll probably want to re-review
> when I send it.
Yes, I figured that at least the 1st patch would need to be reworked...
> Then I'll re-send the rest as a non-RFC series.
Won't they need to be rebased against 3 fixes?
[...]
> Thanks for the review!
> Paul
MBR, Sergey