Re: [PATCHv2 0/3] Allow ZRAM to use any zpool-compatible backend

From: Vitaly Wool
Date: Fri Dec 20 2019 - 01:04:20 EST


On Fri, Dec 20, 2019 at 4:14 AM Minchan Kim <minchan@xxxxxxxxxx> wrote:

<snip>
> Look https://lkml.org/lkml/2019/10/29/1169
>
> z3fold read is 15% faster *only* when when compression ratio is bad below 50%
> since zsmalloc involves copy operation if the object is located in the
> boundary of discrete pages. It's never popular workload.
> Even, once write is involved(write-only, mixed read-write), z3fold is always
> slow. Think about that swap-in could cause swap out in the field because devices
> are usually under memory pressure. Also, look at the memory usage.
> zsmalloc saves bigger memory for all of compression ratios.

Yes I remember that. Since your measurements were done on "an x86" without
providing any detail on the actual platform used, they are as good as none.

~Vitaly