Raspberry Pi Model B UnixBench results using a UHS-I card
Posted July 14, 2012 
Comments(6)
Comments(6) Here’s the UnixBench v5.1.3 result of my Raspberry Pi (model B). I’m using a SanDisk Extreme Pro UHS-1 card (up to 95MB/s) in the RPi’s SD card slot and the RPi is running Debian “Squeeze”.
# # # # # # # ##### ###### # # #### # #
# # ## # # # # # # # ## # # # # #
# # # # # # ## ##### ##### # # # # ######
# # # # # # ## # # # # # # # # #
# # # ## # # # # # # # ## # # # #
#### # # # # # ##### ###### # # #### # #
Version 5.1.3 Based on the Byte Magazine Unix Benchmark
Multi-CPU version Version 5 revisions by Ian Smith,
Sunnyvale, CA, USA
January 13, 2011 johantheghost at yahoo period com
1 x Dhrystone 2 using register variables 1 2 3 4 5 6 7 8 9 10
1 x Double-Precision Whetstone 1 2 3 4 5 6 7 8 9 10
1 x Execl Throughput 1 2 3
1 x File Copy 1024 bufsize 2000 maxblocks 1 2 3
1 x File Copy 256 bufsize 500 maxblocks 1 2 3
1 x File Copy 4096 bufsize 8000 maxblocks 1 2 3
1 x Pipe Throughput 1 2 3 4 5 6 7 8 9 10
1 x Pipe-based Context Switching 1 2 3 4 5 6 7 8 9 10
1 x Process Creation 1 2 3
1 x System Call Overhead 1 2 3 4 5 6 7 8 9 10
1 x Shell Scripts (1 concurrent) 1 2 3
1 x Shell Scripts (8 concurrent) 1 2 3
========================================================================
BYTE UNIX Benchmarks (Version 5.1.3)
System: rpi: GNU/Linux
OS: GNU/Linux -- 3.1.9+ -- #138 PREEMPT Tue Jun 26 16:27:52 BST 2012
Machine: armv6l (unknown)
Language: en_US.utf8 (charmap="UTF-8", collate="UTF-8")
17:22:06 up 3 days, 18:33, 1 user, load average: 0.36, 0.13, 0.11; runlevel 2
------------------------------------------------------------------------
Benchmark Run: Sat Jul 14 2012 17:22:06 - 17:50:25
0 CPUs in system; running 1 parallel copy of tests
Dhrystone 2 using register variables 1258319.6 lps (10.0 s, 7 samples)
Double-Precision Whetstone 29.7 MWIPS (9.8 s, 7 samples)
Execl Throughput 223.1 lps (29.9 s, 2 samples)
File Copy 1024 bufsize 2000 maxblocks 26948.5 KBps (30.0 s, 2 samples)
File Copy 256 bufsize 500 maxblocks 8150.0 KBps (30.0 s, 2 samples)
File Copy 4096 bufsize 8000 maxblocks 64959.4 KBps (30.0 s, 2 samples)
Pipe Throughput 123432.0 lps (10.0 s, 7 samples)
Pipe-based Context Switching 15023.0 lps (10.0 s, 7 samples)
Process Creation 634.1 lps (30.0 s, 2 samples)
Shell Scripts (1 concurrent) 436.1 lpm (60.1 s, 2 samples)
Shell Scripts (8 concurrent) 56.1 lpm (60.9 s, 2 samples)
System Call Overhead 253373.7 lps (10.0 s, 7 samples)
System Benchmarks Index Values BASELINE RESULT INDEX
Dhrystone 2 using register variables 116700.0 1258319.6 107.8
Double-Precision Whetstone 55.0 29.7 5.4
Execl Throughput 43.0 223.1 51.9
File Copy 1024 bufsize 2000 maxblocks 3960.0 26948.5 68.1
File Copy 256 bufsize 500 maxblocks 1655.0 8150.0 49.2
File Copy 4096 bufsize 8000 maxblocks 5800.0 64959.4 112.0
Pipe Throughput 12440.0 123432.0 99.2
Pipe-based Context Switching 4000.0 15023.0 37.6
Process Creation 126.0 634.1 50.3
Shell Scripts (1 concurrent) 42.4 436.1 102.9
Shell Scripts (8 concurrent) 6.0 56.1 93.5
System Call Overhead 15000.0 253373.7 168.9
========
System Benchmarks Index Score 62.3
And here’s the result of the rather popular sequential disk write (dd) test:
dd if=/dev/zero of=test bs=64k count=16k conv=fdatasync
16384+0 records in
16384+0 records out
1073741824 bytes (1.1 GB) copied, 52.0759 s, 20.6 MB/s
That looks pretty low to me. Maybe the SD card controller on the RPi can’t handle the UHS-1 speed?
hdparm -t /dev/mmcblk0
/dev/mmcblk0:
Timing buffered disk reads: 62 MB in 3.07 seconds = 20.19 MB/sec
Am I reading those results correctly? A write speed of 26.3 MB/s for 1K size chunks and 63.4 MB/s for 4K sized chunks? The dd result by Jan would seem to indicate a mere 20.6 MB/s, but was Jan’s result using the SanDisk Extreme Pro UHS-1 card? Also a bs of 64K is another factor. Seems to be an apples and oranges thing. Although, I’d have half expected a better rating at 64K. SanDisk advertises a 90 MB/s rating for that card. I’d be curious to see the much cheaper Extreme, which boasts a 45 MB/s, rating. I’m considering one for my Pi.
Thanks for sharing! I’ll save some $ and get a cheaper SD card then.
Brian, it looks like the limiting factor is the RPi’s bus/SD card controller whatever, which maxes out at around 20MB/s when using the provided Debian “Squeeze” OS image. On my notebook, the card performs around 3 times better for these tests.
I have a Sandisk Extreme 32GB rated at 45MB/s and got the same ~20MB/s buffered reading speed as well. The card fares a much better reading speed closer to the advertised speed in an USB-3.0 card reader.
In short, get an SD card that can do 20MB/s for current generation of RPi is the best bang of bucks.