From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13AD2C77B7D for ; Sat, 20 May 2023 18:18:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231354AbjETSSN (ORCPT ); Sat, 20 May 2023 14:18:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39650 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231201AbjETSSJ (ORCPT ); Sat, 20 May 2023 14:18:09 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B6D86133; Sat, 20 May 2023 11:18:07 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3A95760B51; Sat, 20 May 2023 18:18:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 50C19C433D2; Sat, 20 May 2023 18:18:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1684606686; bh=n9ZnwZEc9i33GUPwN6TPJuA8sji3D0eDeT8xlZW5un0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mcFmK+uUxc1MS+AQZrVHqHP+BzK4gYyxaz192l6a3mIxqJf3lzqCnU6+m9okGk4D4 hz0RSmnQZyiSaOmrdHOrEv0r3Mm2F8CFZJ01i7XyTHyMWfJXX+GlH16pLDugRmmRt/ dt5DbD2Zm/zAvXBPByWIwo3L8/nzaJ21mx+SjuW4vx+0KY8KroAIaBvu6HmpynNTlR mtWZulyxT39HMaqcv9XoOq5+HZuX49i7COxBOgLpiZRwRvKJFo/czoL0T4JIQj3k0b ydCGTgNt7dN5wO4yXz2g8IkPckTnhBDScLGbPILMD/xebCBvMLOM2ISkI2VbVqA65/ Ug0efFzJbXLrg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Kan Liang , Stephane Eranian , Peter Zijlstra , Sasha Levin , mingo@redhat.com, acme@kernel.org, tglx@linutronix.de, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH AUTOSEL 6.3 04/18] perf/x86/intel/ds: Flush PEBS DS when changing PEBS_DATA_CFG Date: Sat, 20 May 2023 14:17:36 -0400 Message-Id: <20230520181750.823365-4-sashal@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230520181750.823365-1-sashal@kernel.org> References: <20230520181750.823365-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org From: Kan Liang [ Upstream commit b752ea0c28e3f7f0aaaad6abf84f735eebc37a60 ] Several similar kernel warnings can be triggered, [56605.607840] CPU0 PEBS record size 0, expected 32, config 0 cpuc->record_size=208 when the below commands are running in parallel for a while on SPR. while true; do perf record --no-buildid -a --intr-regs=AX \ -e cpu/event=0xd0,umask=0x81/pp \ -c 10003 -o /dev/null ./triad; done & while true; do perf record -o /tmp/out -W -d \ -e '{ld_blocks.store_forward:period=1000000, \ MEM_TRANS_RETIRED.LOAD_LATENCY:u:precise=2:ldlat=4}' \ -c 1037 ./triad; done The triad program is just the generation of loads/stores. The warnings are triggered when an unexpected PEBS record (with a different config and size) is found. A system-wide PEBS event with the large PEBS config may be enabled during a context switch. Some PEBS records for the system-wide PEBS may be generated while the old task is sched out but the new one hasn't been sched in yet. When the new task is sched in, the cpuc->pebs_record_size may be updated for the per-task PEBS events. So the existing system-wide PEBS records have a different size from the later PEBS records. The PEBS buffer should be flushed right before the hardware is reprogrammed. The new size and threshold should be updated after the old buffer has been flushed. Reported-by: Stephane Eranian Suggested-by: Peter Zijlstra (Intel) Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20230421184529.3320912-1-kan.liang@linux.intel.com Signed-off-by: Sasha Levin --- arch/x86/events/intel/ds.c | 56 ++++++++++++++++++------------- arch/x86/include/asm/perf_event.h | 3 ++ 2 files changed, 35 insertions(+), 24 deletions(-) diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c index a2e566e53076e..df88576d6b2a5 100644 --- a/arch/x86/events/intel/ds.c +++ b/arch/x86/events/intel/ds.c @@ -1229,12 +1229,14 @@ pebs_update_state(bool needed_cb, struct cpu_hw_events *cpuc, struct perf_event *event, bool add) { struct pmu *pmu = event->pmu; + /* * Make sure we get updated with the first PEBS * event. It will trigger also during removal, but * that does not hurt: */ - bool update = cpuc->n_pebs == 1; + if (cpuc->n_pebs == 1) + cpuc->pebs_data_cfg = PEBS_UPDATE_DS_SW; if (needed_cb != pebs_needs_sched_cb(cpuc)) { if (!needed_cb) @@ -1242,7 +1244,7 @@ pebs_update_state(bool needed_cb, struct cpu_hw_events *cpuc, else perf_sched_cb_dec(pmu); - update = true; + cpuc->pebs_data_cfg |= PEBS_UPDATE_DS_SW; } /* @@ -1252,24 +1254,13 @@ pebs_update_state(bool needed_cb, struct cpu_hw_events *cpuc, if (x86_pmu.intel_cap.pebs_baseline && add) { u64 pebs_data_cfg; - /* Clear pebs_data_cfg and pebs_record_size for first PEBS. */ - if (cpuc->n_pebs == 1) { - cpuc->pebs_data_cfg = 0; - cpuc->pebs_record_size = sizeof(struct pebs_basic); - } - pebs_data_cfg = pebs_update_adaptive_cfg(event); - - /* Update pebs_record_size if new event requires more data. */ - if (pebs_data_cfg & ~cpuc->pebs_data_cfg) { - cpuc->pebs_data_cfg |= pebs_data_cfg; - adaptive_pebs_record_size_update(); - update = true; - } + /* + * Be sure to update the thresholds when we change the record. + */ + if (pebs_data_cfg & ~cpuc->pebs_data_cfg) + cpuc->pebs_data_cfg |= pebs_data_cfg | PEBS_UPDATE_DS_SW; } - - if (update) - pebs_update_threshold(cpuc); } void intel_pmu_pebs_add(struct perf_event *event) @@ -1326,9 +1317,17 @@ static void intel_pmu_pebs_via_pt_enable(struct perf_event *event) wrmsrl(base + idx, value); } +static inline void intel_pmu_drain_large_pebs(struct cpu_hw_events *cpuc) +{ + if (cpuc->n_pebs == cpuc->n_large_pebs && + cpuc->n_pebs != cpuc->n_pebs_via_pt) + intel_pmu_drain_pebs_buffer(); +} + void intel_pmu_pebs_enable(struct perf_event *event) { struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); + u64 pebs_data_cfg = cpuc->pebs_data_cfg & ~PEBS_UPDATE_DS_SW; struct hw_perf_event *hwc = &event->hw; struct debug_store *ds = cpuc->ds; unsigned int idx = hwc->idx; @@ -1344,11 +1343,22 @@ void intel_pmu_pebs_enable(struct perf_event *event) if (x86_pmu.intel_cap.pebs_baseline) { hwc->config |= ICL_EVENTSEL_ADAPTIVE; - if (cpuc->pebs_data_cfg != cpuc->active_pebs_data_cfg) { - wrmsrl(MSR_PEBS_DATA_CFG, cpuc->pebs_data_cfg); - cpuc->active_pebs_data_cfg = cpuc->pebs_data_cfg; + if (pebs_data_cfg != cpuc->active_pebs_data_cfg) { + /* + * drain_pebs() assumes uniform record size; + * hence we need to drain when changing said + * size. + */ + intel_pmu_drain_large_pebs(cpuc); + adaptive_pebs_record_size_update(); + wrmsrl(MSR_PEBS_DATA_CFG, pebs_data_cfg); + cpuc->active_pebs_data_cfg = pebs_data_cfg; } } + if (cpuc->pebs_data_cfg & PEBS_UPDATE_DS_SW) { + cpuc->pebs_data_cfg = pebs_data_cfg; + pebs_update_threshold(cpuc); + } if (idx >= INTEL_PMC_IDX_FIXED) { if (x86_pmu.intel_cap.pebs_format < 5) @@ -1391,9 +1401,7 @@ void intel_pmu_pebs_disable(struct perf_event *event) struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); struct hw_perf_event *hwc = &event->hw; - if (cpuc->n_pebs == cpuc->n_large_pebs && - cpuc->n_pebs != cpuc->n_pebs_via_pt) - intel_pmu_drain_pebs_buffer(); + intel_pmu_drain_large_pebs(cpuc); cpuc->pebs_enabled &= ~(1ULL << hwc->idx); diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h index 8fc15ed5e60bb..abf09882f58b6 100644 --- a/arch/x86/include/asm/perf_event.h +++ b/arch/x86/include/asm/perf_event.h @@ -121,6 +121,9 @@ #define PEBS_DATACFG_LBRS BIT_ULL(3) #define PEBS_DATACFG_LBR_SHIFT 24 +/* Steal the highest bit of pebs_data_cfg for SW usage */ +#define PEBS_UPDATE_DS_SW BIT_ULL(63) + /* * Intel "Architectural Performance Monitoring" CPUID * detection/enumeration details: -- 2.39.2