|| ||Fengguang Wu <firstname.lastname@example.org>|
|| ||Jens Axboe <email@example.com>|
|| ||[PATCH 0/7] [RFC] iosched: make a difference between read/readahead requests|
|| ||Sat, 24 Jun 2006 10:03:58 +0800|
|| ||firstname.lastname@example.org, Andrew Morton <email@example.com>,
Nick Piggin <firstname.lastname@example.org>,
Lubos Lunak <email@example.com>|
This patchset does two jobs:
1) do io schedule differently on READ/READA requests.
- to help improve I/O latency and throughput
2) do notification/action on READA => READ events
- to make the elevators better informed
- to prevent the priority inversion problem
- also brings some CPU overheads*
(*) I'm not able to provide the numbers at the moment.
But sure for the next time.
The patches come in two groups:
1) explicitly schedule READA requests
Note: currently only the deadline elevator is touched.
[PATCH 1/7] iosched: introduce WRITEA
[PATCH 2/7] iosched: introduce parameter deadline.reada_expire
[PATCH 3/7] iosched: introduce deadline_add_drq_fifo()
[PATCH 4/7] iosched: submit READA requests on possible readahead code path
2) notify/act on pending reads
Naming issue: how about pending_read/need_page/... for kick_page?
[PATCH 5/7] iosched: introduce elv_kick_page()
[PATCH 6/7] iosched: run elv_kick_page() on sync read
[PATCH 7/7] iosched: introduce deadline_kick_page()
Most overheads should be in functions deadline_kick_page() and
deadline_add_drq_fifo(). I'll explore the details later.
Any comments are welcome, thanks.
Dept. Automation University of Science and Technology of China