Re: CVS commit: src/sys

[christos%astron.com@localhost (Christos Zoulas)]

In article <20111228124228.C4D8614A345%mail.netbsd.org@localhost>,
YAMAMOTO Takashi <yamt%mwd.biglobe.ne.jp@localhost> wrote:
>hi,
>
>> On Dec 21,  5:07am, yamt%mwd.biglobe.ne.jp@localhost (YAMAMOTO Takashi) 
>> wrote:
>> -- Subject: Re: CVS commit: src/sys
>> 
>> | why?
>> | i thought the reason of having this as a separate member was performance.
>> 
>> All the code paths that use NBIO check bits in so_state... I would like to
>> see the benchmark that proves this.
>
>it's about the fcntl side, for which you added more locking.
>

For FIONBIO... Even if you construct a synthetic benchmark that
turns on and off blocking I/O for a socket continuously, and the
locking overhead proves to be larger than the system call overhead
(which it may very well be), I doubt that you'll find any real
program that calls ioctl(so, FIONBIO, ...) frequently enough to
make a difference.

I really think that Andy confused it with FIONREAD (hence the comment),
which can be called quite frequently (and it is still unlocked).

christos