From: Peter Zijlstra <peterz@infradead.org>
To: Davidlohr Bueso <davidlohr@hp.com>
Cc: tglx@linutronix.de, mingo@kernel.org, dvhart@linux.intel.com,
paulmck@linux.vnet.ibm.com, torvalds@linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: Re: futex funkiness -- massive lockups
Date: Wed, 5 Mar 2014 09:16:44 +0100 [thread overview]
Message-ID: <20140305081644.GR9987@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1393983784.2512.40.camel@buesod1.americas.hpqcorp.net>
On Tue, Mar 04, 2014 at 05:43:04PM -0800, Davidlohr Bueso wrote:
> Hi,
>
> A large amount of lockups are seen on a 480 core system doing some sort
> of database-like workload. All except one are soft lockups. This is a
> SLES11 system with most of the recent futex changes backported,
> including commits 63b1a816, b0c29f79, 99b60ce6, a52b89eb, 0d00c7b2,
> 5cdec2d8 and f12d5bfc.
>
> [212071.494920] [<ffffffff810589e5>] load_balance+0xa5/0x470
> [212071.494920] [<ffffffff81058f13>] rebalance_domains+0x163/0x220
> [212071.494920] [<ffffffff81059144>] run_rebalance_domains+0x44/0x60
> [212071.494920] [<ffffffff810677df>] __do_softirq+0x11f/0x260
> [212071.494920] [<ffffffff81469fdc>] call_softirq+0x1c/0x30
> [212071.494920] [<ffffffff81004435>] do_softirq+0x65/0xa0
> [212071.494920] [<ffffffff810675a5>] irq_exit+0xc5/0xe0
> [212071.494920] [<ffffffff81026588>] smp_apic_timer_interrupt+0x68/0xa0
> [212071.494920] [<ffffffff81469773>] apic_timer_interrupt+0x13/0x20
> [212071.494920] [<ffffffff81460ec5>] _raw_spin_lock+0x15/0x20
> [212071.494920] [<ffffffff8109626a>] futex_wake+0xba/0x180
> [212071.494920] [<ffffffff810987c4>] do_futex+0x94/0x1c0
> [212071.494920] [<ffffffff81098972>] sys_futex+0x82/0x170
> [212071.494920] [<ffffffff81468d92>] system_call_fastpath+0x16/0x1b
>
Like Linus said; that looks like its stuck in the load balancer. Now 480
is certainly more CPUs that usual. However, SGI ran with lots more and I
don't recall them seeing soft lockups from this.
OTOH I do know the softirq runs for more than a softirq should; even on
moderate systems.
next prev parent reply other threads:[~2014-03-05 8:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-05 1:43 futex funkiness -- massive lockups Davidlohr Bueso
2014-03-05 3:36 ` Linus Torvalds
2014-03-05 4:45 ` Davidlohr Bueso
2014-03-05 8:16 ` Peter Zijlstra [this message]
2014-03-05 9:01 ` Ingo Molnar
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