Hi Neil,

IOzone is a filesystem benchmark tool. The benchmark generates and measures a variety of file operations

As there are several parameters/possibilities, first I reduced command to perform few operations, only one file size set to 102400 kB and 5 record size (4k / 16k / 512k / 1024k / 16384k)

Unit for results provided by iozone command are in kBytes/sec  for read /reread /write and rewrite operations

For each measure I expect a variability less than 10%

I extract some specific results (from file.txt provided previous week)

Measure (kBytes/sec) done with File size = 102400 kB and reclen = 512k

With Lava					Average	Ecart Type	Variability
	Try1	Try2	Try3	Try4
write	11783	6564	11733	9203	9821	2483	25,3%
rewrite	12771	5818	12630	10038	10314	3250	31,5%
read	41083	24049	40799	27819	33438	8801	26,3%
reread	41161	23488	40862	27586	33274	9090	27,3%
Without Lava					Average	Ecart Type	Variability
	Try1	Try2	Try3	Try4
write	13434	13623	13476	13487	13505	82	0,6%
rewrite	13479	13688	13498	13520	13546	96	0,7%
read	40785	40794	40870	40829	40820	39	0,1%
reread	40882	40722	40874	40829	40827	74	0,2%

See following complete log of one execution (try2 without Lava)

iozone -az -i0 -i1 -I -e -s 100M -r 4k -r 16k -r 512k -r 1024k -r 16384k -f /mnt_emmc//tmp/iozone.tmp

                Iozone: Performance Test of File I/O

                        Version $Revision: 3.465 $

                               Compiled for 32 bit mode.

                               Build: linux-arm

                Contributors:William Norcott, Don Capps, Isom Crawford, Kirby Collins

                             Al Slater, Scott Rhine, Mike Wisner, Ken Goss

                             Steve Landherr, Brad Smith, Mark Kelly, Dr. Alain CYR,

                             Randy Dunlap, Mark Montague, Dan Million, Gavin Brebner,

                             Jean-Marc Zucconi, Jeff Blomberg, Benny Halevy, Dave Boone,

                             Erik Habbinga, Kris Strecker, Walter Wong, Joshua Root,

                             Fabrice Bacchella, Zhenghua Xue, Qin Li, Darren Sawyer,

                             Vangel Bojaxhi, Ben England, Vikentsi Lapa,

                             Alexey Skidanov.

                Run began: Thu Dec 14 08:30:40 2017

                Auto Mode

                Cross over of record size disabled.

                O_DIRECT feature enabled

                Include fsync in write timing

                File size set to 102400 kB

                Record Size 4 kB

                Record Size 16 kB

                Record Size 512 kB

                Record Size 1024 kB

                Record Size 16384 kB

                Command line used: iozone -az -i0 -i1 -I -e -s 100M -r 4k -r 16k -r 512k -r 1024k -r 16384k -f /mnt_emmc//tmp/iozone.tmp

                Output is in kBytes/sec

                Time Resolution = 0.000001 seconds.

                Processor cache size set to 1024 kBytes.

                Processor cache line size set to 32 bytes.

                File stride size set to 17 * record size.

                                                              random    random     bkwd    record    stride                                   

              kB  reclen    write  rewrite    read    reread    read     write     read   rewrite      read   fwrite frewrite    fread  freread

          102400       4     8567    10445    14289    14290                                                                                 

          102400      16    13654    14436    23454    23418                                                                                  

          102400     512    13623    13688    40794    40722

          102400    1024    14294    14393    41432    41456                                                                                  

          102400   16384    13743    14035    42327    42425                                                                                 

iozone test complete.

Florence

From: Lava-users [mailto:lava-users-bounces@lists.linaro.org] On Behalf Of Neil Williams
Sent: mardi 30 janvier 2018 08:23
To: Anibal Limon <anibal.limon@linaro.org>
Cc: lava-users@lists.linaro.org
Subject: Re: [Lava-users] IOZone test to measure performance of DUT

On 29 January 2018 at 16:48, Anibal Limon <anibal.limon@linaro.org> wrote:

On 26 January 2018 at 08:14, Steve McIntyre <steve.mcintyre@linaro.org> wrote:

On Fri, Jan 26, 2018 at 02:04:52PM +0000, Florence ROUGER JUNG wrote:
>That's right, at first I used following command  and there was some output  to the terminal
>       iozone $OPT -f /mnt_emmc/tmp/iozone.tmp | tee result.log
>
>But now I redirect output
>       iozone $OPT -f /mnt_emmc/tmp/iozone.tmp > iozone.log 2>&1
>performance are better but remain not homogeneous with Lava

OK, that does surprise me. I could imagine that running a test with
lots of output to the serial port could slow things down, but if
you're redirecting everything then it should be making no difference
at all. What kind of variance are you seeing?

I've been working on a long test run definition with a lot of serial console output (Piglit), here is what i found [1],  looks like is related to this thread.

Anibal: It is not related - this thread is concerning output from scripts running on the DUT and writing to the DUT filesystem without sending output anywhere else.

Your Piglit report is different - you are reporting activity on the dispatcher (telnet & lava-run). Steve addresses the difference in the paragraph above your reply.

Florence: please provide more information on what variance is actually being seen? The numbers quoted so far are meaningless without the context of what amount of variance is expected and what the numbers actually represent.

--

Neil Williams
=============
neil.williams@linaro.org
http://www.linux.codehelp.co.uk/