From: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
To: linux-hotplug@vger.kernel.org
Subject: Good news for threading!
Date: Mon, 25 May 2009 13:46:25 +0000 [thread overview]
Message-ID: <4A1AA131.7000202@tuffmail.co.uk> (raw)
I solved one of the reservations that held me back on threaded udevd. I
still have some other concerns to work on, but I'm feeling much more
optimistic now.
Replacing processes with threads reduced page faults (copy-on-write) by
60-80%, but that _still_ left over 10% of udevd time in page fault overhead.
I've discovered I can reduce this overhead much further by marking
thread stacks with MADV_DONTFORK. When a thread needs to fork an
external program, it can temporarily unmark its own thread stack.
Disclaimer: I have no idea why this should reduce the number of page
faults. I could be getting something horribly wrong. But even if it's
wrong, at least it gives me a new angle on this problem.
Alan
next reply other threads:[~2009-05-25 13:46 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-25 13:46 Alan Jenkins [this message]
2009-05-25 19:09 ` Good news for threading! Kay Sievers
2009-05-25 20:28 ` Alan Jenkins
2009-05-25 23:52 ` Kay Sievers
2009-05-26 7:03 ` Scott James Remnant
2009-05-26 9:32 ` Alan Jenkins
2009-05-26 9:36 ` Alan Jenkins
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