Well, because at the time the code was written (oh about 18 years ago) pthread_timed_lock didn’t exist in Solaris.
From: Brian Bockelman
Sent: Tuesday, August 28, 2018 6:43 PM
To: xrootd/xrootd
Cc: Subscribed
Subject: Re: [xrootd/xrootd] XrdHttp loses requests under modest concurrency (#810)
The ofs_Stall is not coming from the OSS but from here:
https://github.com/xrootd/xrootd/blob/master/src/XrdOfs/XrdOfsHandle.cc#L203
It appears there's a modest contention on the file descriptor table -- one that does not particularly play well with what appears to be an ad-hoc implementation of a timed lock:
https://github.com/xrootd/xrootd/blob/master/src/XrdOfs/XrdOfsHandle.cc#L504
It's not obvious why one would utilize that instead of a wrapper around pthread_mutex_timedlock; it appears the hand-rolled version has similar guarantees as the standard function but worse performance.
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