From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752305AbcCASMS (ORCPT ); Tue, 1 Mar 2016 13:12:18 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:38833 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751139AbcCASMR (ORCPT ); Tue, 1 Mar 2016 13:12:17 -0500 Date: Tue, 1 Mar 2016 19:12:07 +0100 From: Peter Zijlstra To: Jiri Olsa Cc: Andi Kleen , "Liang, Kan" , Arnaldo Carvalho de Melo , Ingo Molnar , Stephane Eranian , Wang Nan , "zheng.z.yan@intel.com" , LKML Subject: Re: [BUG] Core2 cpu triggers hard lockup with perf test Message-ID: <20160301181207.GZ6356@twins.programming.kicks-ass.net> References: <20160227123636.GB30858@krava.redhat.com> <37D7C6CF3E00A74B8858931C1DB2F0770589EC94@SHSMSX103.ccr.corp.intel.com> <20160301091703.GN6356@twins.programming.kicks-ass.net> <20160301110651.GA15260@krava.redhat.com> <20160301145105.GQ5083@two.firstfloor.org> <20160301145909.GS6356@twins.programming.kicks-ass.net> <20160301171722.GA2666@krava.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160301171722.GA2666@krava.redhat.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 01, 2016 at 06:17:22PM +0100, Jiri Olsa wrote: > I tried what Andy suggested below (not sure what he meant by Merom, > I took PEBS format0 instead), works for me Model 15, see intel_pmu_init(). But you're actually running on a Penryn I suspect, since we disabled PEBS for Merom. There's also a bunch of Atoms that uses PEBS format 0, no idea if they're affected too. > --- > diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c > index c8a243d6fc82..c4a1a769bae7 100644 > --- a/arch/x86/events/intel/ds.c > +++ b/arch/x86/events/intel/ds.c > @@ -269,7 +269,7 @@ static int alloc_pebs_buffer(int cpu) > if (!x86_pmu.pebs) > return 0; > > - buffer = kzalloc_node(PEBS_BUFFER_SIZE, GFP_KERNEL, node); > + buffer = kzalloc_node(x86_pmu.pebs_buffer_size, GFP_KERNEL, node); > if (unlikely(!buffer)) > return -ENOMEM; > > @@ -286,7 +286,7 @@ static int alloc_pebs_buffer(int cpu) > per_cpu(insn_buffer, cpu) = ibuffer; > } > > - max = PEBS_BUFFER_SIZE / x86_pmu.pebs_record_size; > + max = x86_pmu.pebs_buffer_size / x86_pmu.pebs_record_size; > > ds->pebs_buffer_base = (u64)(unsigned long)buffer; > ds->pebs_index = ds->pebs_buffer_base; > @@ -1319,6 +1319,7 @@ void __init intel_ds_init(void) > > x86_pmu.bts = boot_cpu_has(X86_FEATURE_BTS); > x86_pmu.pebs = boot_cpu_has(X86_FEATURE_PEBS); > + x86_pmu.pebs_buffer_size = PEBS_BUFFER_SIZE; > if (x86_pmu.pebs) { > char pebs_type = x86_pmu.intel_cap.pebs_trap ? '+' : '-'; > int format = x86_pmu.intel_cap.pebs_format; > @@ -1327,6 +1328,7 @@ void __init intel_ds_init(void) > case 0: > pr_cont("PEBS fmt0%c, ", pebs_type); > x86_pmu.pebs_record_size = sizeof(struct pebs_record_core); At the very least this wants a comment along the lines of: /* * Using >PAGE_SIZE buffers makes the WRMSR to * PERF_GLOBAL_CTRL in intel_pmu_enable_all() * mysteriously hang on Core2. * * As a workaround, we don't do this. */ > + x86_pmu.pebs_buffer_size = PAGE_SIZE; > x86_pmu.drain_pebs = intel_pmu_drain_pebs_core; > break; > > diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h > index 7bb61e32fb29..1ab6279fed1d 100644 > --- a/arch/x86/events/perf_event.h > +++ b/arch/x86/events/perf_event.h > @@ -586,6 +586,7 @@ struct x86_pmu { > pebs_broken :1, > pebs_prec_dist :1; > int pebs_record_size; > + int pebs_buffer_size; > void (*drain_pebs)(struct pt_regs *regs); > struct event_constraint *pebs_constraints; > void (*pebs_aliases)(struct perf_event *event);