horrid USB Storage write performance (Petalinux 2014.2)

Hello Ben,

I am not sure if your poor write performance is due to a slow USB Flash Device, the older version of PetaLinux you are using, or some other problem with your setup or methodology.

While we do not have any formal testing one of my colleagues just ran a quick test using PetaLinux 2015.2.1 on a MicroZed with the following results:

As you can see his test achieved 208200247/30.368 sec for ~7.514 MB/sec  for a USB Flash read operation and 208200247/38.493 sec for ~5.928  MB/sec for a USB Flash write operation.

He said that a test using PetaLinux 2014.4 had similar results.

-Gary

Hey Gary!

Thanks for the results.

I was using a Class 10 microSD with a USB2.0 capable USB Flash disk (just for your reference.)

I installed petalinux 2015.2 in preparation to move to it -- so I'll look to trying that sooner than later.

Your results help me a lot.

(with a 1.4MB file, I was getting like 14second copies to USB flash from /tmp <which is RAM> and 1.8second copies to microSD for the same file from RAM)

Thanks again!

-Ben

As an update to this: Moving to PetaLinux 2015.4 indeed bumped the uSD write speeds (for a class 10) from 1MB/s to about 5MB/s (haven't more exact yet -- but my application timestamps and shows around a 5x improvement right away)

Cheers,

-Ben

Hey Gary,

 I've been asked to revisit this to see if i can squeeze more performance out of this system.

I'm using a Samsung SSD connected to the USB port of the microZed020 and my write performance appears to be around 900KB/s

I'm still using Petalinux 2015.4 -- and no other changes except getting USB running have been made.

Can you verify this is about what you get (or hopefully better with some kernel tweaks or a petalinux update)??

Thanks,

 -Ben

Hello Ben,

I copied the PetaLinux 2015.4 BSP for the MicroZed 7020 from the MicroZed Reference Designs and Tutorials page and copied the images to a uSD Card with no modifications:

http://zedboard.org/support/design/1519/10

I booted up and then connected a vanilla 10 year old USB Flash stick with a large file (bigfile_232mb.zip) on it to the MicroZed 7020 USB port and performed the same tests we used in the post above last year. Here are the results:

By my calculations the USB read performance was 243364008/15.762s for ~ 15.43 MB/sec and the USB write performance was 243364008/11.951s for ~ 20.36 MB/sec.

So even better than before and 15 to 20 times better than you are seeing. I don't know what is causing the difference in your performance but you might want to start with the 'stock' MicroZed 2015.4 BSP we have and see if the issue is your PetaLinux configuration or something to do with your SSD.

-Gary

Hi Gary - thanks for the quick response.

I know the SSD gets a little over 25MB/s hooked through to my linux server (CentOS)... so I don't think that's it.

I'm definitely not getting those performance levels --- Thanks for confirming I should be getting better than what I'm seeing.

I'll see about throwing together the stock BSP.

I'll be back -- but at least I'm not wandering around in the dark.

 -Ben
 

Hi Gary -- thanks for doing that. I just did the same.

I found a few things worthy of note:

1.   After setting up the default environment that comes with the BSP -- any time "petalinux-config" is called -- even if no changes are made, the scripts corrupt system-conf.dtsi gets some of the USB information removed and the compile fails. It must be put back by manually.
2.   you have to use sync and time that too. I found just a copy isn't enough and will reports less accurate numbers as the USB write cache hasn't emptied yet.

So with that, my results were:

•   USB -> Magnetic HDISK was about 22MB/s
•   USB -> SSD style FLASH Disk was about 25MB/s
•   USB -> PenDrive style FLASH was about 2.3MB/s

So SSD's (with maybe better caching and writing algorithms) and hard drives work fabulous.

not sure what the difference is between the petalinux build setup I was using versus this BSP version. (I used my .BIT file which was built using the AvNet TCL scripts to setup the FPGA project. (shrug))

Hopefully I'll find out.

Currently, I think the FPGA is still booting with my old BOOT.BIN -- so when I move my apps over to this project... and then lastly a .BIT file -- I'll keep track if something breaks and when.

But this is a good start. This is the kind of performance I need.

Thanks!