Re: [RFC/RFT v2 0/3] Introduce GRO support to cpumap codebase

[Alexander Lobakin <aleksander.lobakin@intel.com>]

From: Daniel Xu <dxu@dxuuu.xyz>
Date: Fri, 22 Nov 2024 17:10:06 -0700

> Hi Olek,
> 
> Here are the results.
> 
> On Wed, Nov 13, 2024 at 03:39:13PM GMT, Daniel Xu wrote:
>>
>>
>> On Tue, Nov 12, 2024, at 9:43 AM, Alexander Lobakin wrote:

[...]

> Baseline (again)
> 
> 	Transactions	Latency P50 (s)	Latency P90 (s)	Latency P99 (s)			Throughput (Mbit/s)
> Run 1	3169917	        0.00007295	0.00007871	0.00009343		Run 1	21749.43
> Run 2	3228290	        0.00007103	0.00007679	0.00009215		Run 2	21897.17
> Run 3	3226746	        0.00007231	0.00007871	0.00009087		Run 3	21906.82
> Run 4	3191258	        0.00007231	0.00007743	0.00009087		Run 4	21155.15
> Run 5	3235653	        0.00007231	0.00007743	0.00008703		Run 5	21397.06
> Average	3210372.8	0.000072182	0.000077814	0.00009087		Average	21621.126
> 
> cpumap v2 Olek
> 
> 	Transactions	Latency P50 (s)	Latency P90 (s)	Latency P99 (s)			Throughput (Mbit/s)
> Run 1	3253651	        0.00007167	0.00007807	0.00009343		Run 1	13497.57
> Run 2	3221492	        0.00007231	0.00007743	0.00009087		Run 2	12115.53
> Run 3	3296453	        0.00007039	0.00007807	0.00009087		Run 3	12323.38
> Run 4	3254460	        0.00007167	0.00007807	0.00009087		Run 4	12901.88
> Run 5	3173327	        0.00007295	0.00007871	0.00009215		Run 5	12593.22
> Average	3239876.6	0.000071798	0.00007807	0.000091638		Average	12686.316
> Delta	0.92%	        -0.53%	        0.33%	        0.85%			        -41.32%
> 
> 
> It's very interesting that we see -40% tput w/ the patches. I went back

Oh no, I messed up something =\

Could you please also test not the whole series, but patches 1-3 (up to
"bpf:cpumap: switch to GRO...") and 1-4 (up to "bpf: cpumap: reuse skb
array...")? Would be great to see whether this implementation works
worse right from the start or I just broke something later on.

> and double checked and it seems the numbers are right. Here's the
> some output from some profiles I took with:
> 
>     perf record -e cycles:k -a -- sleep 10
>     perf --no-pager diff perf.data.baseline perf.data.withpatches > ...
> 
>     # Event 'cycles:k'
>     # Baseline  Delta Abs  Shared Object                                                    Symbol
>          6.13%     -3.60%  [kernel.kallsyms]                                                [k] _copy_to_iter

BTW, what CONFIG_HZ do you have on the kernel you're testing with?

Thanks,
Olek