Async IO on Linux
- From: "Hostetter, Jay M" <JHostetter@xxxxxxxxxxxxxxxxxxxx>
- To: <Oracle-L@xxxxxxxxxxxxx>
- Date: Thu, 21 Sep 2006 15:40:14 -0400
I'm testing 10gR2 on a new Linux box. I decided to fiddle with enabling
async IO. To test the async IO, I imported a table and I also ran
several queries . I ran these tests one at a time (e.g. the queries and
imports were not running simultaneously). I see NO performance
difference for my import or queries with async IO enabled. I expected
to see some performance difference (meaing change in elapsed time).
Does async IO only help when you have multiple sessions performing IO
simultaneously?
Redhat Linux 2.6.9-5.ELsmp
Oracle 10.2.0.1.0
I enabled async IO as follows:
$cd $ORACLE_HOME/rdbms/lib
$ln -s /usr/lib/libaio.so.1 skgaio.o
$make PL_ORALIBS=-laio -f ins_rdbms.mk async_on
filesystemio_options =asynch
disk_asynch_io=true
Stats change when I check slabinfo, so it appears as though async io is
enabled:
cat /proc/slabinfo | grep -e kio -e name
As a side note, enabling the deadline scheduler DID reduce the time it
took for an import (elevator=deadline in /etc/grub.conf). The import
went from 26 minutes to 11 minutes.
Thank you,
Jay
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