Slow IO on ElCapitan

All your general support questions for OpenZFS on OS X.

Re: Slow IO on ElCapitan

Postby incumbent » Mon Apr 25, 2016 8:59 am

There have been a slew of changes to USB in El Capitan that have affected a lot of people in different ways.

If a USB 3 device is slow, make sure it's connected to XHCI instead of EHCI somehow; browsing the device tree in ioregistryexplorer (or if you're a ninja just use `ioreg`) and/or seeing what System Information says (240Mbps/5Gbps) for the link can sometimes show a problem. I am more familiar with this issue manifesting on Hacs but I've seen some Apple Discussions with Mac users reporting weird USB 3 behavior or issues.

My tl;dr assessment is that Apple started defining the hardware differently (arguably more correctly according to people that apparently know AHCI/DSDT a lot better than I do) and there are some changes in behavior that should have been better across the board for Mac users but isn't always the case. On the Hac(k)intosh side this has often manifested with EHCI bus issues (and people having to re-name their EHCI devices to work around it) with most electing to route all USB to XHCI and let it sort it out. This is usually OK, but I've had instances where a USB 3 device in a hub is fine and functional at USB 3 SuperSpeed but after a reboot is only seen as High Speed USB 2 in the same port -- it's also causing many users to hit a limit on the number of USB devices that can be attached.
incumbent
 
Posts: 40
Joined: Mon Apr 25, 2016 8:52 am

Re: Slow IO on ElCapitan

Postby sebu06 » Thu May 12, 2016 12:34 am

Hi,
sorry - somehow I was not informed by email that there were new replies in this thread, thus the late reaction. The device should be connected to XHCI, this is the output of ioreg:
Code: Select all
      +-o IOResources  <class IOResources, id 0x100000113, registered, matched, active, busy 0 (1040 ms), retain 41>
      +-o AppleUSBHostResources  <class AppleUSBHostResources, id 0x100000208, registered, matched, active, busy 0 (494 ms), retain 41>
      | +-o AppleUSBLegacyRoot  <class AppleUSBLegacyRoot, id 0x100000209, registered, matched, active, busy 0 (492 ms), retain 34>
      |   +-o AppleUSBEHCI@1a000000  <class AppleUSBController, id 0x1000002bb, registered, matched, active, busy 0 (100 ms), retain 11>
      |   +-o AppleUSBXHCI@14000000  <class AppleUSBController, id 0x100000907, registered, matched, active, busy 0 (14 ms), retain 9>
      |     +-o Root Hub Simulation Simulation@14000000  <class AppleUSBRootHubDevice, id 0x100000908, registered, matched, active, busy 0 (2 ms), retain 10>
      |     | +-o PenCommService  <class IOUSBDeviceUserClientV2, id 0x10000090f, !registered, !matched, active, busy 0, retain 5>
      |     +-o BUP Slim BK@14400000  <class AppleUSBDevice, id 0x100000909, registered, matched, active, busy 0 (13 ms), retain 14>
      |       +-o PenCommService  <class IOUSBDeviceUserClientV2, id 0x100000912, !registered, !matched, active, busy 0, retain 5>
      |       +-o AppleUSBInterface@0  <class AppleUSBInterface, id 0x100000916, registered, matched, active, busy 0 (9 ms), retain 5>


@Brendon: I would rather not revert to the previous OSX version, but I have an old MBP with SnowLion on it. Whenever I should decide to update that one, I will measure the speed before and after the upgrade.

Best,
Sebastian
sebu06
 
Posts: 4
Joined: Wed Apr 20, 2016 3:36 am

Re: Slow IO on ElCapitan

Postby incumbent » Thu May 12, 2016 9:45 am

Full stop. I can't help but notice this is a BUP Slim BK device. It is, as you saw, correctly being fed to XHCI but are you accounting for the fact that it's a single 3-platter 5400RPM disk when making your observations on performance?

I'm not saying something isn't wrong, but I wouldn't expect much from a single device of that specification. I'd just be glad that data made it there eventually — I have a few similarly spec'ed USB 3 devices and I can convert at least one of them into a zpool to give you some reference if it would satisfy your curiosity? One is a Toshiba branded 500GB device, and I also have a USB 2 Toshiba 500 I can compare it to. I may be able to add a 1TB Hitachi to the mix if I can shuffle some stuff around.
incumbent
 
Posts: 40
Joined: Mon Apr 25, 2016 8:52 am

Previous

Return to General Help

Who is online

Users browsing this forum: Google [Bot] and 25 guests

cron