lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Sun, 22 Dec 2013 04:07:27 +0100
From:	Mike Galbraith <>
To:	Sebastian Andrzej Siewior <>
	Steven Rostedt <>,, Thomas Gleixner <>,
	"Paul E. McKenney" <>
Subject: Re: [PATCH] rcu: Eliminate softirq processing from rcutree

On Sat, 2013-12-21 at 20:39 +0100, Sebastian Andrzej Siewior wrote: 
> From: "Paul E. McKenney" <>
> Running RCU out of softirq is a problem for some workloads that would
> like to manage RCU core processing independently of other softirq work,
> for example, setting kthread priority.  This commit therefore moves the
> RCU core work from softirq to a per-CPU/per-flavor SCHED_OTHER kthread
> named rcuc.  The SCHED_OTHER approach avoids the scalability problems
> that appeared with the earlier attempt to move RCU core processing to
> from softirq to kthreads.  That said, kernels built with RCU_BOOST=y
> will run the rcuc kthreads at the RCU-boosting priority.

I'll take this for a spin on my 64 core test box.

I'm pretty sure I'll still end up having to split softirq threads again
though, as big box has been unable to meet jitter requirements without,
and last upstream rt kernel tested still couldn't.


Hm.  Another thing I'll have to check again is btrfs locking fix, and
generic IO deadlocks if you don't pull your plug upon first rtmutex
block.  In 3.0, both were required for box to survive heavy fs pounding.
Oh yeah, and the pain of rt tasks playing idle balance for SCHED_OTHER
tasks, and nohz balancing crud, and cpupri cost when cores are isolated
and and.. sigh, big boxen _suck_ ;-)

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists