Re: [PATCH net-next v7 0/8] fix two bugs related to page_pool

[Jesper Dangaard Brouer <hawk@kernel.org>]

On 17/01/2025 12.35, Yunsheng Lin wrote:
> On 2025/1/17 2:02, Jesper Dangaard Brouer wrote:
> 
>>
>> Benchmark (bench_page_pool_simple) results from before and after
>> patchset with patches 1-5m and rcu lock removal as requested.
>>
>> | Test name  |Cycles |   1-5 |    | Nanosec |    1-5 |        |      % |
>> | (tasklet_*)|Before | After |diff|  Before |  After |   diff | change |
>> |------------+-------+-------+----+---------+--------+--------+--------|
>> | fast_path  |    19 |    19 |   0|   5.399 |  5.492 |  0.093 |    1.7 |
>> | ptr_ring   |    54 |    57 |   3|  15.090 | 15.849 |  0.759 |    5.0 |
>> | slow       |   238 |   284 |  46|  66.134 | 78.909 | 12.775 |   19.3 |
>> #+TBLFM: $4=$3-$2::$7=$6-$5::$8=(($7/$5)*100);%.1f
>>
>> This test with patches 1-5 looks much better regarding performance.
> 
> Thanks for the testing.
> 
> Is there any notiable performance variation during different test running
> for the same built kernel in your machine?
> 

My machine have quite stable performance for this benchmark.


>> https://github.com/xdp-project/xdp-project/blob/main/areas/mem/page_pool07_bench_DMA_fix.org#e5-1650-pp01-dma-fix-v7-p1-5

Like documented in above link. I have also increased the loops count for
the test to get it more stable, given this will be measured over a
longer period.

  modprobe bench_page_pool_simple loops=100000000


>> Kernel:
>>   - 6.13.0-rc6-pp01-DMA-fix-v7-p1-5+ #5 SMP PREEMPT_DYNAMIC Thu Jan 16 18:06:53 CET 2025 x86_64 GNU/Linux
>>
>> Machine: Intel(R) Xeon(R) CPU E5-1650 v4 @ 3.60GHz
>>
>> modprobe bench_page_pool_simple loops=100000000
>>
>> Raw data:
>> [  187.309423] bench_page_pool_simple: time_bench_page_pool01_fast_path(): Cannot use page_pool fast-path
>> [  187.872849] time_bench: Type:no-softirq-page_pool01 Per elem: 19 cycles(tsc) 5.539 ns (step:0) - (measurement period time:0.553906443 sec time_interval:553906443) - (invoke count:100000000 tsc_interval:1994123064)
>> [  187.892023] bench_page_pool_simple: time_bench_page_pool02_ptr_ring(): Cannot use page_pool fast-path
>> [  189.611070] time_bench: Type:no-softirq-page_pool02 Per elem: 61 cycles(tsc) 17.095 ns (step:0) - (measurement period time:1.709580367 sec time_interval:1709580367) - (invoke count:100000000 tsc_interval:6154679394)
>> [  189.630414] bench_page_pool_simple: time_bench_page_pool03_slow(): Cannot use page_pool fast-path
>> [  197.222387] time_bench: Type:no-softirq-page_pool03 Per elem: 272 cycles(tsc) 75.826 ns (step:0) - (measurement period time:7.582681388 sec time_interval:7582681388) - (invoke count:100000000 tsc_interval:27298499214)
>> [  197.241926] bench_page_pool_simple: pp_tasklet_handler(): in_serving_softirq fast-path
>> [  197.249968] bench_page_pool_simple: time_bench_page_pool01_fast_path(): in_serving_softirq fast-path
>> [  197.808470] time_bench: Type:tasklet_page_pool01_fast_path Per elem: 19 cycles(tsc) 5.492 ns (step:0) - (measurement period time:0.549225541 sec time_interval:549225541) - (invoke count:100000000 tsc_interval:1977272238)
>> [  197.828174] bench_page_pool_simple: time_bench_page_pool02_ptr_ring(): in_serving_softirq fast-path
>> [  199.422305] time_bench: Type:tasklet_page_pool02_ptr_ring Per elem: 57 cycles(tsc) 15.849 ns (step:0) - (measurement period time:1.584920736 sec time_interval:1584920736) - (invoke count:100000000 tsc_interval:5705890830)
>> [  199.442087] bench_page_pool_simple: time_bench_page_pool03_slow(): in_serving_softirq fast-path
>> [  207.342120] time_bench: Type:tasklet_page_pool03_slow Per elem: 284 cycles(tsc) 78.909 ns (step:0) - (measurement period time:7.890955151 sec time_interval:7890955151) - (invoke count:100000000 tsc_interval:28408319289)
>>