Re: [PATCH] power: use hugepage memory for queue list entry structure

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 20/02/2025 17:45, Stephen Hemminger wrote:
> On Thu, 20 Feb 2025 16:39:52 +0000
> Konstantin Ananyev <konstantin.ananyev@huawei.com> wrote:
> 
>>> -----Original Message-----
>>> From: Stephen Hemminger <stephen@networkplumber.org>
>>> Sent: Thursday, February 20, 2025 4:12 PM
>>> To: lihuisong (C) <lihuisong@huawei.com>
>>> Cc: dev@dpdk.org; thomas@monjalon.net; david.hunt@intel.com; anatoly.burakov@intel.com; sivaprasad.tummala@amd.com;
>>> liuyonglong <liuyonglong@huawei.com>
>>> Subject: Re: [PATCH] power: use hugepage memory for queue list entry structure
>>>
>>> On Thu, 20 Feb 2025 17:01:53 +0800
>>> "lihuisong (C)" <lihuisong@huawei.com> wrote:
>>>    
>>>>> The queue_list_entry structure data is used in rx_callback of io path
>>>>> when enable PMD Power Management. However its memory is currently from
>>>>> normal heap memory. For better performance, use hugepage memory to
>>>>> replace it.
>>>>>
>>>>> Signed-off-by: Huisong Li <lihuisong@huawei.com>
>>>
>>> How is that in a hot path where this could matter?
>>
>> AFAIU - it is used in RX/TX callbacks that power library installs,
>> so I presume will get hit on every eth_rx_burst/tx_burst calls.
>>
>>> The safety rails in rte_malloc() are much less than regular malloc().
>>> I prefer some degree of safety from checkers and malloc library internals.
>>
>> Didn't get your point - what's suddenly wrong with rte_malloc()?
> 
> Coverity and Gcc analyzer treat malloc as special case.
> With attributes rte_malloc gets similar treatment but not quite as much.
> Also internally, malloc and free have more heap pool sanity checks.
> In name of performance, those don't exist in rte_malloc().
> Lastly hugepages are limited resource, so they should only be used when needed.

The last thing I would associate with rte_malloc is performance. I'm not 
sure I follow - which "sanity checks" were omitted from rte_malloc "in 
the name of performance" that are present in regular malloc?

-- 
Thanks,
Anatoly