|| ||Mingming Cao <email@example.com>|
|| ||Andrew Morton <firstname.lastname@example.org>|
|| ||[PATCH 0/5] multiple block allocation to current ext3|
|| ||Tue, 10 Jan 2006 15:26:01 -0800|
|| ||email@example.com, firstname.lastname@example.org,
"Stephen C. Tweedie" <email@example.com>,
Currently ext3_get_block() only map or allocate one block at a time.
This is quite inefficient for sequential IO workload.
I have posted a early implements a simply multiple block map and
allocation with current ext3. The basic idea is allocating the 1st
block in the existing way, and attempting to allocate the next adjacent
blocks on a best effort basis. More description about the
implementation could be found here:
The following the latest version of the patch: break the original patch
into 5 patches, re-worked some logicals, and fixed some bugs. The break
[patch 1] Adding map multiple blocks at a time in ext3_get_blocks()
[patch 2] Extend ext3_get_blocks() to support multiple block allocation
[patch 3] Implement multiple block allocation in ext3-try-to-allocate
(called via ext3_new_block()).
[patch 4] Proper accounting updates in ext3_new_blocks()
[patch 5] Adjust reservation window size properly (by the given number
of blocks to allocate) before block allocation to increase the
possibility of allocating multiple blocks in a single call.
Tests done so far includes fsx,tiobench and dbench. The following
numbers collected from Direct IO tests (1G file creation/read) shows
the system time have been greatly reduced (more than 50% on my 8 cpu
system) with the patches.
1G file DIO write:
real 0m31.275s 0m31.161s
user 0m0.000s 0m0.000s
sys 0m3.384s 0m0.564s
1G file DIO read:
real 0m30.733s 0m30.624s
user 0m0.000s 0m0.004s
sys 0m0.748s 0m0.380s
Some previous test we did on buffered IO with using multiple blocks
allocation and delayed allocation shows noticeable improvement on
throughput and system time.
Patches against 2.6.15. Please consider to add to mm tree.