Subject: [linux-audio-dev] hdrbench on FreeBSD MUCH better filesystem latencies than on Linux :-(
From: Benno Senoner (sbenno_AT_gardena.net)
Date: Sun Apr 23 2000 - 14:45:42 EEST
Hi,
Tommy Hallgren was so nice to send me some results of hdrbench on his FreeBSD
box.
The bufferusage of hdrbench is amazingly low, compared to Linux:
http://www.linuxdj.com/hdrbench/freebsd-18-18.gif
mere 10K samples (40kbytes) while streaming 36 tracks of 180KB/sec each, while
on linux I get these bad (compared to freebsd) results:
http://www.linuxdj.com/hdrbench/graph-18-18.gif
up to 150K samples buffer usage. 15times more ..
:-(
(Notice that my box is almost identical to Tommy's one dual Celeron with IBM
7200rpm EIDE UDMA disk
I don't understand why this can happen since freebsd basically has to overcome
to the same metadata updating problems, synching, buffer cache flushing etc.
Any linux guru knows, why FreeBSD has such an edge over linux in this test.
( the I/O performance in MB/sec is quite the same, but filesystem latencies,
and especially the stalls during the disk I/O are really tiny compared to
Linux) ?
for more infos on hdrbench:
http://www.linuxdj.com/hdrbench.
Benno.
On Sat, 22 Apr 2000, Tommy Hallgren wrote:
>
> Hi Benno!
>
> I always read your postings to linux-kern with interest even though I don't use
> Linux myself.
>
> I thought you might find the results of hdrbench running on my system
> interesting. My system is a 2x366MHz Celeron running on a Abit BP6 mainboard. I
> have 192MB RAM and a nice 7200RPM IDE IBM drive. The operating system is
> FreeBSD 4.0-STABLE freshly compiled yesterday.
>
> I didn't use any buffering option on the commandline. Also, I had to modify
> your program on a few places, the mlockall() part had to go and the other
> changes were just simple <linux/soundcard.h> -> <sys/soundcard.h> changes.
>
> The graph output is attached to this mail. Also, I've attached the output of my
> "dmesg".
>
> I'd like to hear comments from you.
>
> Regards, Tommy
>
>
> =====
> Tommy Hallgren(tommy_AT_frontpartner.com)
> Briljantg. 31, SE-421 49, Göteborg
> Tel.: +46 (0)709 - 312 404 (GSM)
> Tel.: +46 (0)31 - 47 65 28 (Home)
>
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