lkml.org 
[lkml]   [2014]   [Dec]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [dm-devel] [PATCH v2] staging: writeboost: Add dm-writeboost
On 12/12/14 01:42, Akira Hayakawa wrote:
> 1. Writeboost shouldn't split the bio into 4KB chunks.
> No. It is necessary.
> I know WALB (https://github.com/starpos/walb) logs data without
> splitting but the data structure becomes complicated.
> If you read my code carefully, you will notice that splitting
> helps the design simplicity and performance.

This is the first time I see someone claiming that reducing the request
size improves performance. I don't know any SSD model for which
splitting requests improves performance.

Additionally, since bio's are split by dm-writeboost, this makes me
wonder how atomic writes will ever be supported ? Atomic writes are
being standardized by the T10 SCSI committee. I don't think the Linux
block layer already supports atomic writes today but I expect support
for atomic writes to be added to the block layer sooner or later. See
e.g. http://www.t10.org/doc13.htm / SBC-4 SPC-5 Atomic writes and reads
for the latest draft specification.

Bart.




\
 
 \ /
  Last update: 2014-12-12 10:41    [W:0.158 / U:0.580 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site