From: Mike Travis <travis@sgi.com>
To: Christoph Lameter <cl@linux.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>,
akpm@linuxfoundation.org, rostedt@goodmis.org,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Hedi Berriche <hedi@sgi.com>, Dimitri Sivanich <sivanich@sgi.com>
Subject: Re: [PATCH 31/48] uv: Replace __get_cpu_var
Date: Wed, 05 Mar 2014 18:53:51 -0800 [thread overview]
Message-ID: <5317E33F.5000206@sgi.com> (raw)
In-Reply-To: <alpine.DEB.2.10.1403051547140.16786@nuc>
On 3/5/2014 1:57 PM, Christoph Lameter wrote:
> The driver seems to use local64_t to define a single static instance of a
> counter and then seems to think that it is safe to increment the counter
> from multiple processors using local64_inc and friends. Common
> misunderstanding and a reason why I wanted the this_cpu operations.
>
> The counters seem to be exported via module parameters.. So I guess we
> need to define these per cpu and then sum them up when they need to be
> displayed.
>
> Dimitri?
>
> Maybe lets move this outside of this patchset.
>
Hi Christoph,
I haven't had much chance yet to look over your proposed changes but
FYI, the counters are strictly feedback to insure that there are not
unhandled NMI events from the perf subsystem. The exact count is
irrelevant. IOW, counts in the double or triple digits is okay,
counts > 100,000 is definitely not okay (there are multiple millions
of perf events every 'perf top' refresh.)
I'm not sure if this alters how you want to approach the changes.
Thanks,
Mike
next prev parent reply other threads:[~2014-03-06 2:53 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-14 20:18 [PATCH 00/48] percpu: Consistent per cpu operations V4 Christoph Lameter
2014-02-14 20:18 ` [PATCH 01/48] percpu: Add raw_cpu_ops Christoph Lameter
2014-02-14 20:18 ` [PATCH 02/48] mm: Use raw_cpu ops for determining current NUMA node Christoph Lameter
2014-02-14 20:18 ` Christoph Lameter
2014-02-14 20:18 ` [PATCH 03/48] modules: Use raw_cpu_write for initialization of per cpu refcount Christoph Lameter
2014-02-14 20:18 ` [PATCH 04/48] net: Replace __this_cpu_inc in route.c with raw_cpu_inc Christoph Lameter
2014-02-14 20:18 ` [PATCH 05/48] percpu: Add preemption checks to __this_cpu ops Christoph Lameter
2014-03-04 22:27 ` Andrew Morton
2014-03-04 23:27 ` Steven Rostedt
2014-03-05 3:27 ` Christoph Lameter
2014-03-05 21:34 ` Andrew Morton
2014-02-14 20:18 ` [PATCH 06/48] mm: Replace __get_cpu_var uses with this_cpu_ptr Christoph Lameter
2014-02-14 20:18 ` Christoph Lameter
2014-02-14 20:18 ` [PATCH 07/48] tracing: " Christoph Lameter
2014-02-14 20:18 ` [PATCH 08/48] percpu: Replace __get_cpu_var " Christoph Lameter
2014-02-14 20:18 ` [PATCH 09/48] kernel misc: Replace __get_cpu_var uses Christoph Lameter
2014-02-14 20:18 ` [PATCH 10/48] drivers/char/random: " Christoph Lameter
2014-02-14 20:18 ` [PATCH 11/48] drivers/cpuidle: Replace __get_cpu_var uses for address calculation Christoph Lameter
2014-02-14 20:18 ` [PATCH 12/48] drivers/oprofile: " Christoph Lameter
2014-02-14 20:18 ` [PATCH 13/48] drivers/leds: Replace __get_cpu_var use through this_cpu_ptr Christoph Lameter
2014-02-14 20:18 ` [PATCH 14/48] drivers/clocksource: Replace __get_cpu_var used for address calculation Christoph Lameter
2014-02-14 20:18 ` [PATCH 15/48] parisc: Replace __get_cpu_var uses " Christoph Lameter
2014-02-14 20:18 ` Christoph Lameter
2014-02-14 20:18 ` [PATCH 16/48] metag: " Christoph Lameter
2014-02-14 20:18 ` [PATCH 17/48] drivers/net/ethernet/tile: " Christoph Lameter
2014-02-14 20:18 ` [PATCH 18/48] drivers/net/ethernet/tile: __get_cpu_var call introduced in 3.14 Christoph Lameter
2014-02-14 20:19 ` [PATCH 19/48] tilegx: Another case of get_cpu_var Christoph Lameter
2014-02-14 20:19 ` [PATCH 20/48] time: Replace __get_cpu_var uses Christoph Lameter
2014-02-15 11:33 ` Thomas Gleixner
2014-02-14 20:19 ` [PATCH 21/48] scheduler: Replace __get_cpu_var with this_cpu_ptr Christoph Lameter
2014-02-14 20:19 ` [PATCH 22/48] tick-sched: Fix two new uses of __get_cpu_ptr Christoph Lameter
2014-02-15 11:33 ` Thomas Gleixner
2014-02-14 20:19 ` [PATCH 23/48] block: Replace __this_cpu_ptr with raw_cpu_ptr Christoph Lameter
2014-02-14 20:19 ` [PATCH 24/48] rcu: Replace __this_cpu_ptr uses " Christoph Lameter
2014-02-16 16:17 ` Paul E. McKenney
2014-02-14 20:19 ` [PATCH 25/48] watchdog: Replace __raw_get_cpu_var uses Christoph Lameter
2014-02-14 20:19 ` [PATCH 26/48] net: Replace get_cpu_var through this_cpu_ptr Christoph Lameter
2014-02-14 20:19 ` [PATCH 27/48] md: Replace __this_cpu_ptr with raw_cpu_ptr Christoph Lameter
2014-02-14 20:19 ` [PATCH 28/48] irqchips: Replace __this_cpu_ptr uses Christoph Lameter
2014-02-14 20:19 ` [PATCH 29/48] x86: Replace __get_cpu_var uses Christoph Lameter
2014-02-14 20:19 ` [PATCH 30/48] x86: Change __get_cpu_var calls introduced in 3.14 Christoph Lameter
2014-02-14 20:19 ` [PATCH 31/48] uv: Replace __get_cpu_var Christoph Lameter
2014-03-04 23:02 ` Andrew Morton
2014-03-04 23:42 ` Steven Rostedt
2014-03-04 23:47 ` Andrew Morton
2014-03-05 0:18 ` H. Peter Anvin
2014-03-05 3:31 ` Christoph Lameter
2014-03-05 4:00 ` Andrew Morton
2014-03-05 15:35 ` Christoph Lameter
2014-03-05 21:57 ` Christoph Lameter
2014-03-06 2:53 ` Mike Travis [this message]
2014-03-07 18:16 ` Christoph Lameter
2014-02-14 20:19 ` [PATCH 32/48] arm: Replace __this_cpu_ptr with raw_cpu_ptr Christoph Lameter
2014-02-14 20:19 ` [PATCH 33/48] MIPS: Replace __get_cpu_var uses in FPU emulator Christoph Lameter
2014-02-14 20:19 ` [PATCH 34/48] mips: Replace __get_cpu_var uses Christoph Lameter
2014-02-14 20:19 ` [PATCH 35/48] s390: rename __this_cpu_ptr to raw_cpu_ptr Christoph Lameter
2014-02-14 20:19 ` [PATCH 36/48] s390: Replace __get_cpu_var uses Christoph Lameter
2014-02-14 20:19 ` [PATCH 37/48] s390: Handle new __get_cpu_var calls added in 3.14 Christoph Lameter
2014-02-14 20:19 ` [PATCH 38/48] ia64: Replace __get_cpu_var uses Christoph Lameter
2014-02-14 20:19 ` Christoph Lameter
2014-02-14 20:19 ` [PATCH 39/48] powerpc: " Christoph Lameter
2014-02-15 3:50 ` Benjamin Herrenschmidt
2014-02-15 4:26 ` Steven Rostedt
2014-02-15 7:54 ` Mike Galbraith
2014-02-15 10:00 ` Benjamin Herrenschmidt
2014-02-15 11:29 ` Mike Galbraith
2014-02-15 9:59 ` Benjamin Herrenschmidt
2014-02-15 9:42 ` Peter Zijlstra
2014-02-15 10:01 ` Benjamin Herrenschmidt
2014-02-15 12:07 ` Andreas Schwab
2014-02-15 15:45 ` Peter Zijlstra
2014-02-15 18:12 ` David Woodhouse
2014-02-15 20:32 ` Benjamin Herrenschmidt
2014-02-15 20:52 ` Benjamin Herrenschmidt
2014-02-14 20:19 ` [PATCH 40/48] powerpc: Handle new __get_cpu_var calls in 3.14 Christoph Lameter
2014-02-14 20:19 ` [PATCH 41/48] sparc: Replace __get_cpu_var uses Christoph Lameter
2014-02-14 20:19 ` Christoph Lameter
2014-02-14 20:19 ` [PATCH 42/48] tile: " Christoph Lameter
2014-02-14 20:19 ` [PATCH 43/48] blackfin: " Christoph Lameter
2014-02-14 20:19 ` [PATCH 44/48] avr32: Replace __get_cpu_var with __this_cpu_write Christoph Lameter
2014-02-14 20:19 ` [PATCH 45/48] alpha: Replace __get_cpu_var Christoph Lameter
2014-02-14 20:19 ` [PATCH 46/48] sh: Replace __get_cpu_var uses Christoph Lameter
2014-02-14 20:19 ` Christoph Lameter
2014-02-14 20:19 ` [PATCH 47/48] Remove __get_cpu_var and __raw_get_cpu_var macros [only in 3.16] Christoph Lameter
2014-02-14 20:19 ` [PATCH 48/48] percpu: Remove __this_cpu_ptr Christoph Lameter
2014-03-04 22:27 ` [PATCH 00/48] percpu: Consistent per cpu operations V4 Andrew Morton
2014-03-05 3:29 ` Christoph Lameter
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