linux-kernel - [PATCH 0/8 v2] Introduce CFQ group hierarchical scheduling and "use

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 13 Dec 2010 09:44:10 +0800
From:	Gui Jianfeng <guijianfeng@...fujitsu.com>
To:	Jens Axboe <axboe@...nel.dk>, Vivek Goyal <vgoyal@...hat.com>
CC:	Corrado Zoccolo <czoccolo@...il.com>,
	Chad Talbott <ctalbott@...gle.com>,
	Nauman Rafique <nauman@...gle.com>,
	Divyesh Shah <dpshah@...gle.com>,
	linux kernel mailing list <linux-kernel@...r.kernel.org>
Subject: [PATCH 0/8 v2] Introduce CFQ group hierarchical scheduling and "use_hierarchy"
 interface

Hi

Previously, I posted a patchset to add support of CFQ group hierarchical scheduling
in the way that it puts all CFQ queues in a hidden group and schedules with other 
CFQ group under their parent. The patchset is available here,
http://lkml.org/lkml/2010/8/30/30

Vivek think this approach isn't so instinct that we should treat CFQ queues
and groups at the same level. Here is the new approach for hierarchical 
scheduling based on Vivek's suggestion. The most big change of CFQ is that
it gets rid of cfq_slice_offset logic, and makes use of vdisktime for CFQ
queue scheduling just like CFQ group does. But I still give cfqq some jump 
in vdisktime based on ioprio, thanks for Vivek to point out this. Now CFQ 
queue and CFQ group uses the same scheduling algorithm. 

"use_hierarchy" interface is now added to switch between hierarchical mode
and flat mode. For this time being, this interface only appears in Root Cgroup.

V1 -> V2 Changes:
- Raname "struct io_sched_entity" to "struct cfq_entity" and don't differentiate
  queue_entity and group_entity, just use cfqe instead. 
- Give newly added cfqq a small vdisktime jump accord to its ioprio.
- Make flat mode as default CFQ group scheduling mode.
- Introduce "use_hierarchy" interface.
- Update blkio cgroup documents

[PATCH 1/8 v2] cfq-iosched: Introduce cfq_entity for CFQ queue
[PATCH 2/8 v2] cfq-iosched: Introduce cfq_entity for CFQ group
[PATCH 3/8 v2] cfq-iosched: Introduce vdisktime and io weight for CFQ queue
[PATCH 4/8 v2] cfq-iosched: Extract some common code of service tree handling for CFQ queue and CFQ group
[PATCH 5/8 v2] cfq-iosched: Introduce hierarchical scheduling with CFQ queue and group at the same level
[PATCH 6/8] blkio-cgroup: "use_hierarchy" interface without any functionality
[PATCH 7/8] cfq-iosched: Add flat mode and switch between two modes by "use_hierarchy"
[PATCH 8/8] blkio-cgroup: Document for blkio.use_hierarchy.

Benchmarks:
I made use of Vivek's iostest to perform some benchmarks on my box. I tested different workloads, and
didn't see any performance drop comparing to vanilla kernel. The attached files are some performance
numbers on vanilla Kernel, patched kernel with flat mode and patched kernel with hierarchical mode.

View attachment "patched-flat.log" of type "text/plain" (5304 bytes)

View attachment "patched-hier.log" of type "text/plain" (5304 bytes)

View attachment "vanilla.log" of type "text/plain" (5305 bytes)