[Bug 13266] New: Writing of files to Apple's new "AP" controller model SSD's takes 4x longer.

samba-bugs at samba.org samba-bugs at samba.org
Sun Feb 11 16:53:11 UTC 2018


            Bug ID: 13266
           Summary: Writing of files to Apple's new "AP" controller model
                    SSD's takes 4x longer.
           Product: rsync
           Version: 3.1.3
          Hardware: x64
                OS: Mac OS X
            Status: NEW
          Severity: critical
          Priority: P5
         Component: core
          Assignee: wayned at samba.org
          Reporter: info at danny-s.com
        QA Contact: rsync-qa at samba.org

Created attachment 13953
  --> https://bugzilla.samba.org/attachment.cgi?id=13953&action=edit
2017 MacBook Pro made in 2018 showing "AP" model drive.

I regularly use rsync to deploy roughly 40gb of data to new Macs that come in.
For the past few years this has taken roughly 8-10 minutes to transfer to SSD

A few weeks ago this time suddenly jumped to over 40 minutes with no other
exchanges to hardware.

I've deeply troubleshooted this performance issue and found only one change has
occurred. Originally blaming APFS, i tested with both APFS and HFS read and
write sources. It occurred on both an iMac Pro and two MacBook Pros. macOS has
been forked for the iMac Pro and I considered that perhaps it's build (which my
admin OS was running) had a different SSD kext - however I tried both 10.13.3
17D47 and the iMac Pro build 10.13.3 17D2047 and confirmed the performance
issue on both.

We've been recreating this bug for faster testing by copying the Applications
folder from the source to the destination (with a destination where the
Applications folder doesn't exist, just to get raw copy speed). The folder is
25gb. With Finder, including the lengthy time it takes to pre-scan files, it
copies in 6 minutes, with rsync it's nearly 25 minutes, again about 1 minute
per gb.

I tested on my 2017 MacBook Pro and observed that both Finder and rsync could
copy the data in 6 minutes - same source, destination of my MacBook Pro was
APFS formatted too.

I had seen other MacBook Pros and SSD equipped iMacs come in and all copy with
the correct speed and deploy within 10 minutes.

Finally upon inspecting what is different about the recent MacBook Pros and the
iMac Pro, in the SSD NVME tab they have listed an "AP" model for the SSD
(Presumably Apple with their own controller) my 2017 MacBook Pro that doesn't
show this poor performance has an "SM" model (Samsung).

The only consistent thing on all the systems showing this 4x slower speed with
rsync is that they have AP model SSDs. The MacBook Pro has AP0512J, the iMac
Pro has AP1024M.
My MacBook Pro which works fine and was made just after the refresh is SM1024L.

So I assume Apple has quietly changed to the AP drives (and controller?) in
recent weeks for the MacBook Pro (some "SM" are still coming through which work
fine with rsync) and of course the iMac Pro is shipping with it.

I'll be getting a number of these systems in, so any testing, logs or anything
I can do to get to the bottom of this should be no problem - I have as well
filed a Rdar with Apple as it could be something they need to fix in their own

Attached an SSD model number.

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