From: Andrew Cagney <cagney@redhat.com>
To: frysk <frysk@sourceware.org>
Subject: blocking waitpid based event-loop
Date: Thu, 05 Apr 2007 03:42:00 -0000 [thread overview]
Message-ID: <46147013.90601@redhat.com> (raw)
Hi,
The new core event-loop, that is implemented using a blocking waitpid
call (and not dependent on SIGCHLD), has been fully committed The old
SIGCHLD + WAITPID/NOHANG based event loop had a race where, after a
SIGCHLD, it could call WAITPID/NOHANG before the kernel had made the
corresponding WAITPID event ready; this leading to frysk hanging as it
didn't appear to receive the event.
Not that it is still disabled though. While the FC-5 test results are
identical to the old event-loop, it's managing to generate some
mysterious "unknown pid" messages - perhaps it is working a little too
well :-)
If you want to try the the new event loop, make an obvious tweak to
frysk.proc.Manager.usePoll. I'll look at the possibility of adding an
--event-loop={poll,wait} option.
Next will be merging the ptrace-thread into the event-loop thread
allowing for much of that thread's overhead to be eliminated. After
that Phil and I will see about making frysk use bulk ptrace transfers.
Andrew
reply other threads:[~2007-04-05 3:42 UTC|newest]
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