Re: [tip:perf/core] perf/x86/amd: Add support for AMD NB and L2I "uncore" counters
From: Jacob Shin
Date: Sun Apr 21 2013 - 13:33:57 EST
On Sun, Apr 21, 2013 at 07:02:32PM +0200, Borislav Petkov wrote:
> On Sun, Apr 21, 2013 at 05:48:36AM -0700, tip-bot for Jacob Shin wrote:
> > Commit-ID: c43ca5091a374c1f6778bd7e4a39a5a10735a917
> > Gitweb: http://git.kernel.org/tip/c43ca5091a374c1f6778bd7e4a39a5a10735a917
> > Author: Jacob Shin <jacob.shin@xxxxxxx>
> > AuthorDate: Fri, 19 Apr 2013 16:34:28 -0500
> > Committer: Ingo Molnar <mingo@xxxxxxxxxx>
> > CommitDate: Sun, 21 Apr 2013 11:01:24 +0200
> >
> > perf/x86/amd: Add support for AMD NB and L2I "uncore" counters
> >
> > Add support for AMD Family 15h [and above] northbridge
> > performance counters. MSRs 0xc0010240 ~ 0xc0010247 are shared
> > across all cores that share a common northbridge.
> >
> > Add support for AMD Family 16h L2 performance counters. MSRs
> > 0xc0010230 ~ 0xc0010237 are shared across all cores that share a
> > common L2 cache.
> >
> > We do not enable counter overflow interrupts. Sampling mode and
> > per-thread events are not supported.
>
> Something's fishy with lockdep here:
>
> [ 1.217368] perf: AMD NB counters detected
> [ 1.217438] ------------[ cut here ]------------
> [ 1.217497] WARNING: at kernel/lockdep.c:2590 trace_hardirqs_on_caller+0x1b9/0x1f0()
> [ 1.217572] Hardware name: To be filled by O.E.M.
> [ 1.217624] Modules linked in:
> [ 1.217705] Pid: 0, comm: swapper/1 Not tainted 3.9.0-rc7+ #2
> [ 1.217760] Call Trace:
> [ 1.217810] <IRQ> [<ffffffff8103bd2f>] warn_slowpath_common+0x7f/0xc0
> [ 1.217926] [<ffffffff81130905>] ? new_slab+0x225/0x2a0
> [ 1.217981] [<ffffffff8103bd8a>] warn_slowpath_null+0x1a/0x20
> [ 1.218038] [<ffffffff8109aac9>] trace_hardirqs_on_caller+0x1b9/0x1f0
> [ 1.218095] [<ffffffff8109ab0d>] trace_hardirqs_on+0xd/0x10
> [ 1.218149] [<ffffffff81130905>] new_slab+0x225/0x2a0
> [ 1.218205] [<ffffffff815959d8>] __slab_alloc.isra.57.constprop.60+0x31e/0x454
> [ 1.218281] [<ffffffff8107a813>] ? local_clock+0x43/0x50
> [ 1.218365] [<ffffffff810a62ee>] ? generic_smp_call_function_single_interrupt+0x7e/0x110
> [ 1.218441] [<ffffffff810984e8>] ? trace_hardirqs_off_caller+0x28/0x120
> [ 1.218497] [<ffffffff81131f05>] kmem_cache_alloc_trace+0xb5/0x1f0
> [ 1.218552] [<ffffffff810a62ee>] ? generic_smp_call_function_single_interrupt+0x7e/0x110
> [ 1.218629] [<ffffffff8158b4e1>] amd_uncore_alloc.isra.7+0x1f/0x29
> [ 1.218683] [<ffffffff8158b505>] amd_uncore_cpu_up_prepare+0x1a/0xac
> [ 1.218739] [<ffffffff81a9dfe8>] init_cpu_already_online+0x14/0x26
> [ 1.218794] [<ffffffff8107a813>] ? local_clock+0x43/0x50
> [ 1.218848] [<ffffffff810a630d>] generic_smp_call_function_single_interrupt+0x9d/0x110
> [ 1.218924] [<ffffffff81027157>] smp_call_function_single_interrupt+0x27/0x40
> [ 1.219000] [<ffffffff8159e56f>] call_function_single_interrupt+0x6f/0x80
> [ 1.219620] <EOI> [<ffffffff8100b515>] ? default_idle+0x25/0x270
> [ 1.219735] [<ffffffff8100b513>] ? default_idle+0x23/0x270
> [ 1.219789] [<ffffffff8100c146>] arch_cpu_idle+0x26/0x30
> [ 1.219844] [<ffffffff8108cf1e>] cpu_startup_entry+0x7e/0x3d0
> [ 1.219898] [<ffffffff8158d2c4>] start_secondary+0x1b7/0x1bb
> [ 1.219956] ---[ end trace abe5f11379b64afd ]---
> [ 1.220059] LVT offset 0 assigned for vector 0x400
> [ 1.220140] perf: AMD IBS detected (0x000000ff)
>
Hm .. I think maybe during _init hotplug lock is already held? Let me
investigate ASAP:
+static int __init amd_uncore_init(void)
+{
..snip..
+ get_online_cpus();
+ /* init cpus already online before registering for hotplug notifier */
+ for_each_online_cpu(cpu)
+ smp_call_function_single(cpu, init_cpu_already_online, NULL, 1);
+
+ register_cpu_notifier(&amd_uncore_cpu_notifier_block);
+ put_online_cpus();
..snip..
+device_initcall(amd_uncore_init);
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