Re: [PATCH v3] zram: extend zero pages to same element pages

From: zhouxianrong
Date: Mon Jan 23 2017 - 01:17:59 EST


i am not sure as well about reverse hurting cache.

On 2017/1/23 14:13, Joonsoo Kim wrote:
On Mon, Jan 23, 2017 at 01:47:20PM +0900, Minchan Kim wrote:
Hello,

When I look at first patch, I wanted to use increment loop but didn't
tell to you because that small piece of code is no harmful for readbility
to me so I want to keep author's code rather than pointing the trivial
which is just matter of preference out.

Rather than readiblity, I suspect it might hurt performance and talked
with Namhyung but we cannot find anything decremental loop is bad
compared to incremental. Rather than, many articles have been said
decrement loop is faster like zhouxianrong's mentiond although I don't
think it makes marginal difference.

Joonsoo, why do you think incremental is faster?
zhouxianrong, why do you think decrement loops makes cache problem?

I'm okay either way. Just want to know why you guys think about it.

Hmm... I guess that cache prefetcher works better for forward access
but I'm not sure.

Thanks.


.