Re: [patch V3 00/22] timer: Refactor the timer wheel

From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Eric Dumazet <edumazet@google.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Chris Mason <clm@fb.com>, Arjan van de Ven <arjan@infradead.org>,
	rt@linutronix.de, Rik van Riel <riel@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	George Spelvin <linux@sciencehorizons.net>,
	Len Brown <lenb@kernel.org>,
	Josh Triplett <josh@joshtriplett.org>
Subject: Re: [patch V3 00/22] timer: Refactor the timer wheel
Date: Sun, 26 Jun 2016 21:22:36 -0700	[thread overview]
Message-ID: <20160627042236.GC4309@linux.vnet.ibm.com> (raw)
In-Reply-To: <20160624140325.554996200@linutronix.de>

On Fri, Jun 24, 2016 at 02:32:00PM -0000, Thomas Gleixner wrote:
> This is the third version of the timer wheel rework series. The previous
> versions can be found here:
> 
> V1:   http://lkml.kernel.org/r/20160613070440.950649741@linutronix.de
> V2:   http://lkml.kernel.org/r/20160617121134.417319325@linutronix.de
> 
> The series is also available in git:
> 
>    git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git WIP.timers
> 
> Changes vs. V2:
> 
>  - Removed the 1000Hz granularity reduction to 4ms. Eric explained that
>    datacenter workloads require the granularity in the first level wheel.
> 
>  - Fixed the typo in tilepro. 
> 
>  - Converted sigtimedwait() to hrtimers
> 
>  - To avoid the cascading I extended the wheel by another level. This removes
>    the rarely executed cascading code path, but increases the storage size for
>    HZ>100 slightly. If the tiny folks care, there is an simple option to cut
>    the storage size in half for the price of reduced granularity.
> 
> Thanks,

And this series avoids the strange SRCU behavior that I saw with the
last version.  So looks to be getting there!

I will be torturing it more vigorously, but looking good so far.

							Thanx, Paul

> 	tglx
> 
> ----
>  arch/x86/kernel/apic/x2apic_uv_x.c  |    4 
>  arch/x86/kernel/cpu/mcheck/mce.c    |    4 
>  block/genhd.c                       |    5 
>  drivers/cpufreq/powernv-cpufreq.c   |    5 
>  drivers/mmc/host/jz4740_mmc.c       |    2 
>  drivers/net/ethernet/tile/tilepro.c |    4 
>  drivers/power/bq27xxx_battery.c     |    5 
>  drivers/tty/metag_da.c              |    4 
>  drivers/tty/mips_ejtag_fdc.c        |    4 
>  drivers/usb/host/ohci-hcd.c         |    1 
>  drivers/usb/host/xhci.c             |    2 
>  include/linux/list.h                |   10 
>  include/linux/timer.h               |   34 -
>  kernel/signal.c                     |   24 
>  kernel/time/tick-internal.h         |    1 
>  kernel/time/tick-sched.c            |   46 -
>  kernel/time/timer.c                 | 1096 +++++++++++++++++++++---------------
>  lib/random32.c                      |    1 
>  net/ipv4/inet_connection_sock.c     |    7 
>  net/ipv4/inet_timewait_sock.c       |    5 
>  20 files changed, 734 insertions(+), 530 deletions(-)
> 
> 