Date: Thu, 17 Jan 2002 21:51:04 -0800 (PST) From: Kip Macy <kip@eventdriven.org> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/34016: AIO is 400x slower under -CURRENT Message-ID: <200201180551.g0I5p4v89154@freefall.freebsd.org>
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>Number: 34016
>Category: kern
>Synopsis: AIO is 400x slower under -CURRENT
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Thu Jan 17 22:00:00 PST 2002
>Closed-Date:
>Last-Modified:
>Originator: Kip Macy
>Release: -CURRENT
>Organization:
Extended Solutions
>Environment:
FreeBSD weizen.extendedsolutions.com 5.0-20020106-CURRENT FreeBSD 5.0-20020106-CURRENT #0: Thu Jan 17 15:36:56 PST 2002 root@weizen.extendedsolutions.com:/usr/src/sys/i386/compile/HADES_UP i386
>Description:
I wrote a simple program that uses
the three different completion mechanisms (polling
with aio_error, polling with kevent, and using SIGIO)
to fill up a file by writing 8kb at a time to the
file and then reading 8kb at a time from the file.
The lower the average latency, the more frequently
it can send off a new request and the more quickly
it can complete.
It can be found at:
http://www.eventdriven.org/aio_lat_test.tgz
Don't try using the aiotest_sigio (on FreeBSD), the
siginfo_t doesn't get filled. Yet another PR that I
have to file.
Here are the results (in ms):
10 32MB files
4-way Sun server over NFS
Memory: 4096M real, 924M free, 768M swap in use, 7234M
swap free
> uname -a
SunOS orbit 5.8 Generic_108528-11 sun4u sparc
SUNW,Ultra-Enterprise
> ./aiotest_sigio
write sk_msecs: 112350 max_latency: 560
reads sk_msecs: 119670 max_latency: 780
> ./aiotest_aio_error
write sk_msecs: 45570 max_latency: 240
reads sk_msecs: 48280 max_latency: 630
> ./aiotest_sigio
write sk_msecs: 117260 max_latency: 410
reads sk_msecs: 124100 max_latency: 600
> ./aiotest_aio_error
write sk_msecs: 45050 max_latency: 780
reads sk_msecs: 46550 max_latency: 1530
10 32MB files
600Mhz Laptop local disk UDMA33
Mem: 68M Active, 134M Inact, 30M Wired, 15M Cache, 35M
Buf, 656K Free
kmacy@netherworld [15:20][~/src/bugs] uname -a
FreeBSD netherworld.eventdriven.org 4.5-RC FreeBSD
4.5-RC #1: Wed Jan 16 21:30:55 PST 2002
root@netherworld.e
ventdriven.org:/usr/src/sys/compile/NETHERWORLD i386
kmacy@netherworld [15:08][~/src/bugs/aio]
./aiotest_aio_error
write sk_msecs: 72890 max_latency: 930
reads sk_msecs: 56830 max_latency: 930
kmacy@netherworld [15:11][~/src/bugs/aio]
./aiotest_kevent
write sk_msecs: 71300 max_latency: 1380
reads sk_msecs: 54500 max_latency: 1380
kmacy@netherworld [15:14][~/src/bugs/aio]
./aiotest_aio_error
write sk_msecs: 73970 max_latency: 990
reads sk_msecs: 56790 max_latency: 990
kmacy@netherworld [15:17][~/src/bugs/aio]
./aiotest_kevent
write sk_msecs: 73620 max_latency: 980
reads sk_msecs: 59620 max_latency: 1860
2-way 1.0GHZ
FreeBSD weizen.extendedsolutions.com
5.0-20020106-CURRENT FreeBSD 5.0-20020106-CURRENT #3:
Thu Jan 10 18:58:36 PS
T 2002
root@weizen.extendedsolutions.com:/usr/src/sys/i386/compile/HADES
i386
Mem: 11M Active, 188M Inact, 111M Wired, 1760K Cache,
111M Buf, 691M Free
(~420x slower)
(~420x slower)
10 1MB files local disk (UDMA33)
> aiotest_aio_error
write sk_msecs: 959540 max_latency: 29960
reads sk_msecs: 959970 max_latency: 29960
Same machine compiled UP:
> aiotest_aio_error
write sk_msecs: 810010 max_latency: 29960
reads sk_msecs: 779950 max_latency: 29960
> uname -a
FreeBSD weizen.extendedsolutions.com
5.0-20020106-CURRENT FreeBSD 5.0-20020106-CURRENT #0:
Thu Jan 17 15:36:56 PS
T 2002
root@weizen.extendedsolutions.com:/usr/src/sys/i386/compile/HADES_UP
i386
I wrote a simple program that uses
the three different completion mechanisms (polling
with aio_error, polling with kevent, and using SIGIO)
to fill up a file by writing 8kb at a time to the
file and then reading 8kb at a time from the file.
The lower the average latency, the more frequently
it can send off a new request.
It can be found at:
http://www.eventdriven.org/aio_lat_test.tgz
Don't try using the aiotest_sigio (on FreeBSD), the
siginfo_t doesn't get filled. Yet another PR that I
have to file.
Here are the results (in ms):
10 32MB files
4-way Sun server over NFS
Memory: 4096M real, 924M free, 768M swap in use, 7234M
swap free
> uname -a
SunOS orbit 5.8 Generic_108528-11 sun4u sparc
SUNW,Ultra-Enterprise
> ./aiotest_sigio
write sk_msecs: 112350 max_latency: 560
reads sk_msecs: 119670 max_latency: 780
> ./aiotest_aio_error
write sk_msecs: 45570 max_latency: 240
reads sk_msecs: 48280 max_latency: 630
> ./aiotest_sigio
write sk_msecs: 117260 max_latency: 410
reads sk_msecs: 124100 max_latency: 600
> ./aiotest_aio_error
write sk_msecs: 45050 max_latency: 780
reads sk_msecs: 46550 max_latency: 1530
10 32MB files
600Mhz Laptop local disk UDMA33
Mem: 68M Active, 134M Inact, 30M Wired, 15M Cache, 35M
Buf, 656K Free
kmacy@netherworld [15:20][~/src/bugs] uname -a
FreeBSD netherworld.eventdriven.org 4.5-RC FreeBSD
4.5-RC #1: Wed Jan 16 21:30:55 PST 2002
root@netherworld.e
ventdriven.org:/usr/src/sys/compile/NETHERWORLD i386
kmacy@netherworld [15:08][~/src/bugs/aio]
./aiotest_aio_error
write sk_msecs: 72890 max_latency: 930
reads sk_msecs: 56830 max_latency: 930
kmacy@netherworld [15:11][~/src/bugs/aio]
./aiotest_kevent
write sk_msecs: 71300 max_latency: 1380
reads sk_msecs: 54500 max_latency: 1380
kmacy@netherworld [15:14][~/src/bugs/aio]
./aiotest_aio_error
write sk_msecs: 73970 max_latency: 990
reads sk_msecs: 56790 max_latency: 990
kmacy@netherworld [15:17][~/src/bugs/aio]
./aiotest_kevent
write sk_msecs: 73620 max_latency: 980
reads sk_msecs: 59620 max_latency: 1860
2-way 1.0GHZ
FreeBSD weizen.extendedsolutions.com
5.0-20020106-CURRENT FreeBSD 5.0-20020106-CURRENT #3:
Thu Jan 10 18:58:36 PS
T 2002
root@weizen.extendedsolutions.com:/usr/src/sys/i386/compile/HADES
i386
Mem: 11M Active, 188M Inact, 111M Wired, 1760K Cache,
111M Buf, 691M Free
(~420x slower)
(~420x slower)
10 1MB files local disk (UDMA33)
> aiotest_aio_error
write sk_msecs: 959540 max_latency: 29960
reads sk_msecs: 959970 max_latency: 29960
Same machine compiled UP:
> aiotest_aio_error
write sk_msecs: 810010 max_latency: 29960
reads sk_msecs: 779950 max_latency: 29960
> uname -a
FreeBSD weizen.extendedsolutions.com
5.0-20020106-CURRENT FreeBSD 5.0-20020106-CURRENT #0:
Thu Jan 17 15:36:56 PS
T 2002
root@weizen.extendedsolutions.com:/usr/src/sys/i386/compile/HADES_UP
i386
>How-To-Repeat:
run aiotest_aio_error and aiotest_kevent by compiling the
source from:
http://www.eventdriven.org/aio_lat_test.tgz
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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