[MacPorts] #65239: ccache @4.6.1: process sometimes block for significant periods of time, across multiple macOS releases

[MacPorts]

#65239: ccache @4.6.1: process sometimes block for significant periods of time,
across multiple macOS releases
---------------------+----------------------
 Reporter:  mascguy  |      Owner:  mascguy
     Type:  defect   |     Status:  assigned
 Priority:  Normal   |  Milestone:
Component:  ports    |    Version:  2.7.2
 Keywords:           |       Port:  ccache
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 This issue was first observed via a macOS 10.8 VM. And while that is a
 very clean install - dedicated to MacPorts development and testing -
 initially I chalked it up to something I potentially did.

 Since then, I've now encountered this issue on my physical macOS 10.13
 installation. And that's made me a bit more suspicious. With the caveat
 that it may still be something specific to my installation(s).

 It's important to note that I've been utilizing `ccache` everywhere for a
 few years now - across numerous releases - and have never seen an issue.
 (That includes the previous version, 4.6.0.) In short, this is new with
 version 4.6.1.

 In any event, when the issue occurs, one or more `ccache` processes will
 simply block - with no apparent CPU or disk activity - for many seconds at
 a time. The pauses are very noticeable, and significantly increase port
 build times.

 The temporary workaround is to simply disable use of `ccache`. But that's
 obviously not ideal.

 Specifics for 10.8: There don't appear to be other processes with
 noticeable increases CPU time, or general activity. The `ccache` processes
 simply hang for extended periods.

 As for 10.13: During the hangs, process `opendirectoryd` was very active,
 consuming 300%-ish of CPU time. Ditto for `automountd`, the latter
 consuming 80%-ish of CPU. Cancelling the MacPorts build via Ctrl-C
 resulted in those processes immediately setting down, to idle territory.

 In terms of troubleshooting, more system detail needs to be captured -
 perhaps via the various `dtrace`-related tools - to better understand
 what's happening. As such, assigning the ticket to myself, until more
 investigation is done.

-- 
Ticket URL: <https://trac.macports.org/ticket/65239>
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