Re: [PATCH v2] io_uring: reduced function parameter ctx if possible

[Jens Axboe <axboe@kernel.dk>]

On 11/8/19 7:43 AM, Jackie Liu wrote:
> 
> 
> 在 2019/11/8 22:39, Jens Axboe 写道:
>> On 11/8/19 7:33 AM, Jackie Liu wrote:
>>>
>>>
>>> 在 2019/11/8 22:16, Jens Axboe 写道:
>>>> On 11/8/19 7:11 AM, Jens Axboe wrote:
>>>>> On 11/8/19 12:29 AM, Jackie Liu wrote:
>>>>>> Many times, the core of the function is req, and req has already set
>>>>>> req->ctx at initialization time, so there is no need to pass in from
>>>>>> outside.
>>>>>>
>>>>>> Cleanup, no function change.
>>>>>
>>>>> I was curious if this patch netted us any improvements as well, but it
>>>>> actually blows up the text segment a lot on my laptop. Before the
>>>>> patch:
>>>>>
>>>>>         text	   data	    bss	    dec	    hex	filename
>>>>>        87504	  17588	    256	 105348	  19b84	fs/io_uring.o
>>>>>
>>>>> and after:
>>>>>
>>>>>         text	   data	    bss	    dec	    hex	filename
>>>>>        99098	  17876	    256	 117230	  1c9ee	fs/io_uring.o
>>>>>
>>>>> which seems really odd. I double checked just to be sure!
>>>>>
>>>>> axboe@x1:~ $ gcc --version
>>>>> gcc (Ubuntu 9.2.1-17ubuntu1~18.04.1) 9.2.1 20191102
>>>>
>>>> I took a look at the generated code, and it looks like it's just
>>>> enabling gcc to inline a lot more aggressively.
>>>>
>>>
>>> Hum... I don't have a lot of attention to the size of the generated
>>> code, just to make the code look easier to understand. Will this affect
>>> performance?
>>
>> Seems to be an extreme case on the laptop since I have various debug
>> options enabled for testing in qemu, but it's an increase on my
>> test box with gcc 7.2 as well. I don't think it's anything to worry
>> about, it's just inlining what it should inline. I did a quick perf
>> run and we're not down, so I'm going to apply this one as it cleans
>> up the code and that's always the most important.
>>
> 
> Please wait a moment, I will send the third version, although this patch
> has not been modified, but there is a separate series of patches sent
> together, please reviewed them for me.

OK, will do.

-- 
Jens Axboe