Re: liburing: expose syscalls?

[Jens Axboe <axboe@kernel.dk>]

On 2/1/20 4:30 PM, Pavel Begunkov wrote:
> On 02/02/2020 01:51, Jens Axboe wrote:
>>>> So you just want to have them exposed? I'd be fine with that. I'll
>>>> take a patch :-)
>>>>
>>>
>>> Depends on how it's used, but I'd strive to inline
>>> __sys_io_uring_enter() to remove the extra indirect call into the
>>> shared lib. Though, not sure about packaging and all this stuff. May
>>> be useful to do that for liburing as well.
>>
>> Not sure that actually matters when you're doing a syscall anyway, that
>> should be the long pole for the operation.
>>
> 
> Yeah, but they are starting to stack up (+syscall() from glibc) and can became
> even more layered on the user side.

Not saying it's free, just that I expect the actual system call to dominate.
But I hear what you are saying, this is exactly why the liburing hot path
resides in static inline code, and doesn't require library calls. I did
draw the line on anything that needs a system call, figuring that wasn't
worth over-optimizing.

I could be full of shit, numbers talk!

-- 
Jens Axboe