Re: [PATCH 0/9] x86/clear_huge_page: multi-page clearing

[Raghavendra K T <raghavendra.kt@amd.com>]

On 4/9/2023 4:16 AM, Ankur Arora wrote:
> 
> Raghavendra K T <raghavendra.kt@amd.com> writes:
> 
>> On 4/3/2023 10:52 AM, Ankur Arora wrote:
>>> This series introduces multi-page clearing for hugepages.
> 
>>     *Milan*     mm/clear_huge_page   x86/clear_huge_page   change
>>                             (GB/s)           (GB/s)
>>    pg-sz=2MB                 12.24            17.54    +43.30%
>>     pg-sz=1GB                17.98            37.24   +107.11%
>>
>>
>> Hello Ankur,
>>
>> Was able to test your patches. To summarize, am seeing 2x-3x perf
>> improvement for 2M, 1GB base hugepage sizes.
> 
> Great. Thanks Raghavendra.
> 
>> SUT: Genoa AMD EPYC
>>     Thread(s) per core:  2
>>     Core(s) per socket:  128
>>     Socket(s):           2
>>
>> NUMA:
>>    NUMA node(s):          2
>>    NUMA node0 CPU(s):     0-127,256-383
>>    NUMA node1 CPU(s):     128-255,384-511
>>
>> Test:  Use mmap(MAP_HUGETLB) to demand a fault on 64GB region (NUMA node0), for
>> both base-hugepage-size=2M and 1GB
>>
>> perf stat -r 10 -d -d  numactl -m 0 -N 0 <test>
>>
>> time in seconds elapsed (average of 10 runs) (lower = better)
>>
>> Result:
>> page-size  mm/clear_huge_page   x86/clear_huge_page
>> 2M              5.4567          2.6774
>> 1G              2.64452         1.011281
> 
> So translating into BW, for Genoa we have:
> 
> page-size  mm/clear_huge_page   x86/clear_huge_page
>   2M              11.74              23.97
>   1G              24.24              63.36
> 
> That's a pretty good bump over Milan:
> 
>>     *Milan*     mm/clear_huge_page   x86/clear_huge_page
>>                             (GB/s)           (GB/s)
>>    pg-sz=2MB                12.24            17.54
>>    pg-sz=1GB                17.98            37.24
> 
> Btw, are these numbers with boost=1?
> 

Yes it is. Also a note about config. I had not enabled
GCOV/LOCKSTAT related config because I faced some issues.