Re: O->A loan

[yamt%mwd.biglobe.ne.jp@localhost (YAMAMOTO Takashi)]

hi,

i'd like to start preparing merge of the branch.
we can remove O->A loan later if we decide to do it.
rmind, is it ok for you?

YAMAMOTO Takashi

> On Sat, Feb 18, 2012 at 08:22:35PM +0000, Mindaugas Rasiukevicius wrote:
>> yamt%mwd.biglobe.ne.jp@localhost (YAMAMOTO Takashi) wrote:
>> > hi,
>> > 
>> > i'd like to to either fix or remove O->A page loaning.
>> > 
>> > the biggest problem is the lack of users.  thus no way to test.
>> > any ideas?
>> 
>> After looking at O->A loaning code in yamt-pagecache branch, looking at
>> the benchmark results by Jaime (some data was sent privately, I think)
>> and contemplating about this mechanism - I tend to think that O->A loaning
>> should be removed.  It is a significant code complexity in UVM with some
>> special casing and benchmarks indicate that the benefit is somewhat small.
>> 
>> Does not seem to be worth, does it?
> 
> making this conclusion on the basis of a single benchmark seems premature.
> the use of O->A loaning in that branch is for optimizing reads,
> was that benchmark even doing many reads?
> 
> give me a few days and I'll see if I can come up with some other benchmarks
> that tell a different story.
> 
> -Chuck