From nobody Tue Dec 2 01:06:31 2025 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E342A32572B for ; Mon, 24 Nov 2025 18:55:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.11 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764010509; cv=none; b=BtZ7bleK9e5FfOa95G3tFeQblEFlhYKXTqBGB+MY0b8oy+FouM5G27/m/KvuPro3KN02VrNYTEu88E3oVWANxypVKJXD6dCmiY+cNXB+yXdwFfO0zGzHZww4CG34jS/i4Mhe46a3Q/YLkeuvjXQwx1lzCZ88GaugZk3Z+aUFua8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764010509; c=relaxed/simple; bh=h3Wi7QH7rdtDrArQ1z7cd2FkqfhhsltJzE5lLsizdB0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=W7HFvAYvUmtaeku0ok2KqpVxY25vaIpPish49/td6n5rx7TcwnTZi3kJynI8zBhtoW7OLdGuLNOrdtVhDx9jfyAxe9eHAVsjDABWEgihLSjX2OaG44Bf8Ois184SI2mq2RHSVNBB5iGTnhiX6fzsNNU5yuMatyQCdEqIrC4mxHE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=eRAZlz+O; arc=none smtp.client-ip=192.198.163.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="eRAZlz+O" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1764010508; x=1795546508; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=h3Wi7QH7rdtDrArQ1z7cd2FkqfhhsltJzE5lLsizdB0=; b=eRAZlz+OXBUH2rKI+3BtHdoQEhS9t6dUSqAVsXgEmD3VNosnOKvo0kHZ 3EzOXjsgEVHXCMxagf+lN7slQMkBOqGFYZm/4J1472GpRiUaWP4IRr5ld KlSfvM+6bK/glqZicp8Wc6ZX1Rwjq85MTJSYGuk4rDjxVfaKSnveIYecu OSJ6o5K3x6vPelSQ7RuqDRte9pI8YnPG1JJB/RQ8HII+DL4DIqU4hoCSM 8jHTIUSrCjniNlFEKbtD+/KAZHPUX8lPbuXtFw0RQHTiYmOvhlv2tWdGY m3z+qsO+4QcXkEaNhWvM0zPBog5fAYQ3wb7oCrQ5/KdOxQm/DrLoojnNW A==; X-CSE-ConnectionGUID: hujdeNgIRSiQP9gwAyOICQ== X-CSE-MsgGUID: etJVI/bTQ8GacQG9ExwXLg== X-IronPort-AV: E=McAfee;i="6800,10657,11623"; a="76636859" X-IronPort-AV: E=Sophos;i="6.20,223,1758610800"; d="scan'208";a="76636859" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by fmvoesa105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Nov 2025 10:54:30 -0800 X-CSE-ConnectionGUID: P0uo7BHkTPKQb/QJjCtAfQ== X-CSE-MsgGUID: A2Z1u6jmSlCOvu8lMnDc3g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.20,223,1758610800"; d="scan'208";a="192225029" Received: from rfrazer-mobl3.amr.corp.intel.com (HELO agluck-desk3.home.arpa) ([10.124.222.153]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Nov 2025 10:54:30 -0800 From: Tony Luck To: Fenghua Yu , Reinette Chatre , Maciej Wieczor-Retman , Peter Newman , James Morse , Babu Moger , Drew Fustini , Dave Martin , Chen Yu Cc: x86@kernel.org, linux-kernel@vger.kernel.org, patches@lists.linux.dev, Tony Luck Subject: [PATCH v14 25/32] x86/resctrl: Handle number of RMIDs supported by RDT_RESOURCE_PERF_PKG Date: Mon, 24 Nov 2025 10:54:02 -0800 Message-ID: <20251124185412.24155-26-tony.luck@intel.com> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251124185412.24155-1-tony.luck@intel.com> References: <20251124185412.24155-1-tony.luck@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" There are now three meanings for "number of RMIDs": 1) The number for legacy features enumerated by CPUID leaf 0xF. This is the maximum number of distinct values that can be loaded into MSR_IA32_PQR_ASSOC. Note that systems with Sub-NUMA Cluster mode enabled will force scaling down the CPUID enumerated value by the number of SNC nodes per L3-cache. 2) The number of registers in MMIO space for each event. This is enumerated in the XML files and is the value initialized into event_group::num_rmid. 3) The number of "hardware counters" (this isn't a strictly accurate description of how things work, but serves as a useful analogy that does describe the limitations) feeding to those MMIO registers. This is enumerated in telemetry_region::num_rmids returned from the call to intel_pmt_get_regions_by_feature() Event groups with insufficient "hardware counters" to track all RMIDs are difficult for users to use, since the system may reassign "hardware counter= s" at any time. This means that users cannot reliably collect two consecutive event counts to compute the rate at which events are occurring. Limit an under-resourced event group's number of possible monitor resource groups to the lowest number of "hardware counters" if the user explicitly requests to enable it. Scan all enabled event groups and assign the RDT_RESOURCE_PERF_PKG resource "num_rmid" value to the smallest of these values as this value will be used later to compare against the number of RMIDs supported by other resources to determine how many monitoring resource groups are supported. N.B. Change type of resctrl_mon::num_rmid to u32 to match its usage and the type of event_group::num_rmid so that min(r->num_rmid, e->num_rmid) won't complain about mixing signed and unsigned types. Signed-off-by: Tony Luck --- include/linux/resctrl.h | 2 +- arch/x86/kernel/cpu/resctrl/intel_aet.c | 58 ++++++++++++++++++++++++- fs/resctrl/rdtgroup.c | 2 +- 3 files changed, 59 insertions(+), 3 deletions(-) diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h index 14126d228e61..8623e450619a 100644 --- a/include/linux/resctrl.h +++ b/include/linux/resctrl.h @@ -295,7 +295,7 @@ enum resctrl_schema_fmt { * events of monitor groups created via mkdir. */ struct resctrl_mon { - int num_rmid; + u32 num_rmid; unsigned int mbm_cfg_mask; int num_mbm_cntrs; bool mbm_cntr_assignable; diff --git a/arch/x86/kernel/cpu/resctrl/intel_aet.c b/arch/x86/kernel/cpu/= resctrl/intel_aet.c index 50c8b4c50790..6eff606541ad 100644 --- a/arch/x86/kernel/cpu/resctrl/intel_aet.c +++ b/arch/x86/kernel/cpu/resctrl/intel_aet.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include #include @@ -68,6 +69,10 @@ struct pmt_event { * @force_on: True when "rdt" command line overrides disable of * this @guid due to insufficient @num_rmid. * @guid: Unique number per XML description file. + * @num_rmid: Number of RMIDs supported by this group. May be + * adjusted downwards if enumeration from + * intel_pmt_get_regions_by_feature() indicates fewer + * RMIDs can be tracked simultaneously. * @mmio_size: Number of bytes of MMIO registers for this group. * @num_events: Number of events in this group. * @evts: Array of event descriptors. @@ -81,6 +86,7 @@ struct event_group { =20 /* Remaining fields initialized from XML file. */ u32 guid; + u32 num_rmid; size_t mmio_size; unsigned int num_events; struct pmt_event evts[] __counted_by(num_events); @@ -97,6 +103,7 @@ static struct event_group energy_0x26696143 =3D { .feature =3D FEATURE_PER_RMID_ENERGY_TELEM, .name =3D "energy", .guid =3D 0x26696143, + .num_rmid =3D 576, .mmio_size =3D XML_MMIO_SIZE(576, 2, 3), .num_events =3D 2, .evts =3D { @@ -113,6 +120,7 @@ static struct event_group perf_0x26557651 =3D { .feature =3D FEATURE_PER_RMID_PERF_TELEM, .name =3D "perf", .guid =3D 0x26557651, + .num_rmid =3D 576, .mmio_size =3D XML_MMIO_SIZE(576, 7, 3), .num_events =3D 7, .evts =3D { @@ -208,8 +216,25 @@ static bool group_has_usable_regions(struct event_grou= p *e, struct pmt_feature_g return usable_regions; } =20 +static bool all_regions_have_sufficient_rmid(struct event_group *e, struct= pmt_feature_group *p) +{ + struct telemetry_region *tr; + bool ret =3D true; + + for (int i =3D 0; i < p->count; i++) { + if (!p->regions[i].addr) + continue; + tr =3D &p->regions[i]; + if (tr->num_rmids < e->num_rmid) + ret =3D false; + } + + return ret; +} + static bool enable_events(struct event_group *e, struct pmt_feature_group = *p) { + struct rdt_resource *r =3D &rdt_resources_all[RDT_RESOURCE_PERF_PKG].r_re= sctrl; int skipped_events =3D 0; =20 if (e->force_off) @@ -218,13 +243,44 @@ static bool enable_events(struct event_group *e, stru= ct pmt_feature_group *p) if (!group_has_usable_regions(e, p)) return false; =20 + /* + * Only enable feature with insufficient RMIDs if the user + * requested it from the kernel command line. + */ + if (!all_regions_have_sufficient_rmid(e, p) && !e->force_on) { + pr_info("Feature %s:0x%x not enabled due to insufficient RMIDs\n", + e->name, e->guid); + return false; + } + + for (int i =3D 0; i < p->count; i++) { + if (!p->regions[i].addr) + continue; + /* + * e->num_rmid only adjusted lower if user (via rdt=3D kernel + * parameter) forces an event group with insufficient RMID + * to be enabled. + */ + e->num_rmid =3D min(e->num_rmid, p->regions[i].num_rmids); + } + for (int j =3D 0; j < e->num_events; j++) { if (!resctrl_enable_mon_event(e->evts[j].id, true, e->evts[j].bin_bits, &e->evts[j])) skipped_events++; } =20 - return skipped_events < e->num_events; + if (e->num_events =3D=3D skipped_events) { + pr_info("No events enabled in %s %s:0x%x\n", r->name, e->name, e->guid); + return false; + } + + if (r->mon.num_rmid) + r->mon.num_rmid =3D min(r->mon.num_rmid, e->num_rmid); + else + r->mon.num_rmid =3D e->num_rmid; + + return true; } =20 /* diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c index ac3c6e44b7c5..60ce2390723e 100644 --- a/fs/resctrl/rdtgroup.c +++ b/fs/resctrl/rdtgroup.c @@ -1157,7 +1157,7 @@ static int rdt_num_rmids_show(struct kernfs_open_file= *of, { struct rdt_resource *r =3D rdt_kn_parent_priv(of->kn); =20 - seq_printf(seq, "%d\n", r->mon.num_rmid); + seq_printf(seq, "%u\n", r->mon.num_rmid); =20 return 0; } --=20 2.51.1