Kurt McKee

lessons learned in production

Hey there! This article was written in 2014.

It might not have aged well for any number of reasons, so keep that in mind when reading (or clicking outgoing links!).

Raspberry Pi benchmarks

Posted 6 May 2014 in benchmark and raspberry pi

I had a bit of time today and decided to start using the Raspberry Pi I bought last year. I'm very interested in wringing performance out of it, so to the best of my ability I'm going to measure performance.

I had previously downloaded Arch Linux, so I put that on an SD card. Then I saw a blog post suggesting that a USB drive could increase the performance. So! I adapted the instructions and captured some benchmarks. Quick summary: the USB drive has a slower write speed but a faster read speed...but I have to acknowledge that the results might be better with a different USB drive.

The SD card (a 32GB Sandisk Ultra class 10 32GB card)

[root@alarmpi sdcard]# hdparm -tT /dev/mmcblk0

/dev/mmcblk0:
Timing cached reads:   312 MB in  2.00 seconds = 155.98 MB/sec
Timing buffered disk reads:  54 MB in  3.06 seconds =  17.65 MB/sec

[root@alarmpi sdcard]# sync;time bash -c "(dd if=/dev/zero of=bf bs=8k count=50000; sync)"

50000+0 records in
50000+0 records out
409600000 bytes (410 MB) copied, 39.6374 s, 10.3 MB/s

real    0m41.003s
user    0m0.240s
sys     0m10.230s

[root@alarmpi sdcard]# dd if=bf of=/dev/null

800000+0 records in
800000+0 records out
409600000 bytes (410 MB) copied, 22.3598 s, 18.3 MB/s

The USB drive (a Lexar 8GB Jumpdrive)

[root@alarmpi ~]# hdparm -tT /dev/sda

/dev/sda:
Timing cached reads:   308 MB in  2.00 seconds = 153.90 MB/sec
Timing buffered disk reads:  58 MB in  3.04 seconds =  19.09 MB/sec

[root@alarmpi ~]# sync;time bash -c "(dd if=/dev/zero of=bf bs=8k count=50000; sync)"

50000+0 records in
50000+0 records out
409600000 bytes (410 MB) copied, 41.1666 s, 9.9 MB/s

real    0m45.185s
user    0m0.250s
sys     0m8.210s

[root@alarmpi ~]# dd if=bf of=/dev/null

800000+0 records in
800000+0 records out
409600000 bytes (410 MB) copied, 20.5428 s, 19.9 MB/s