Re: [PATCH 00/19] Cache Aware Scheduling

["Chen, Yu C" <yu.c.chen@intel.com>]

On 10/16/2025 2:26 AM, Madadi Vineeth Reddy wrote:
> On 15/10/25 11:08, Chen, Yu C wrote:
>> On 10/15/2025 5:48 AM, Tim Chen wrote:
>>> On Tue, 2025-10-14 at 17:43 +0530, Madadi Vineeth Reddy wrote:
>>>> Hi Tim,
>>>> Thanks for the patch.
>>>>
>>>> On 11/10/25 23:54, Tim Chen wrote:

[snip]

>>>> ChaCha20-xiangshan improvement in Genoa when llc_aggr_tolerance is set to 100 seems
>>>> due to having relatively lesser thread count. Please provide the numbers
>>>> with default values too. Would like to know numbers on varying loads.
>>>
>>> I'll ask Chen Yu who did the Xiangshan experiments if he has those numbers.
>>>
>>
>> Madadi, do you mean the performance score number or active thread number
>>   when llc_aggr_tolerance is set to 1(default)?
>> The score is around with sched_cache and llc_aggr_tolerance set to 1.
>> The active number is 128 per process, and there are 8 processes when
>> launching the benchmark. I suppose the 128 comes from the number
>> of online CPUs. Please let me know if you need more data.
>>
>> Cced Yangyu who's the author of this benchmark.
> 
> I mean the benchmark result with default value of llc_aggr_tolerance on Genoa
> in comparison to baseline. Knowing number of threads also helps to understand
> the impact.
> 

OK. Here are the full test script and corresponding data:
pepc pstates config --governor performance
pepc pstates config --turbo off
pepc cstates config --disable C2
echo 1 > /proc/sys/kernel/numa_balancing

echo NO_SCHED_CACHE > /sys/kernel/debug/sched/features
make run
sleep 5
sync

echo SCHED_CACHE > /sys/kernel/debug/sched/features
echo 50 > /sys/kernel/debug/sched/llc_overload_pct
echo 1 > /sys/kernel/debug/sched/llc_aggr_tolerance
make run

echo SCHED_CACHE > /sys/kernel/debug/sched/features
# to encourage task aggregation as much as possible
echo 100 > /sys/kernel/debug/sched/llc_overload_pct
echo 100 > /sys/kernel/debug/sched/llc_aggr_tolerance
make run


# ./launch.sh

Host time spent: 51,323ms //baseline
Host time spent: 51,741ms //sched_cache default
Host time spent: 27,934ms //sched_cache aggressive

thanks,
Chenyu