Re: [PATCH v3 0/4] fast poll multishot mode

Hao Xu
2022-05-07T16:06:03Z

在 2022/5/7 下午11:28, Jens Axboe 写道:
> On 5/7/22 8:06 AM, Hao Xu wrote:
>> Let multishot support multishot mode, currently only add accept as its
>> first comsumer.
>
> consumer
>
>> theoretical analysis:
>> 1) when connections come in fast
>> - singleshot:
>> add accept sqe(userpsace) --> accept inline
>
> userspace
>
>> ^ |
>> |-----------------|
>> - multishot:
>> add accept sqe(userspace) --> accept inline
>> ^ |
>> |--*--|
>>
>> we do accept repeatedly in * place until get EAGAIN
>>
>> 2) when connections come in at a low pressure
>> similar thing like 1), we reduce a lot of userspace-kernel context
>> switch and useless vfs_poll()
>
> Overall this looks better than v2 for sure, just some minor tweaks
> needed I believe.
>
> But we still need to consider direct accept with multishot... Should
> probably be an add-on patch as I think it'd get a bit more complicated
> if we need to be able to cheaply find an available free fixed fd slot.
> I'll try and play with that.

I'm tending to use a new mail account to send v4 rather than the gmail
account since the git issue seems to be network related.
I'll also think about the fixed fd problem.

Thanks,
Hao

>