From patchwork Wed Oct 2 07:27:44 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 11170551 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E5DBE1709 for ; Wed, 2 Oct 2019 07:29:18 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CC513222C3 for ; Wed, 2 Oct 2019 07:29:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CC513222C3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iFZ3p-0001rK-41; Wed, 02 Oct 2019 07:28:33 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iFZ3n-0001pT-N5 for xen-devel@lists.xenproject.org; Wed, 02 Oct 2019 07:28:31 +0000 X-Inumbo-ID: 25c0dbd2-e4e6-11e9-9710-12813bfff9fa Received: from mx1.suse.de (unknown [195.135.220.15]) by localhost (Halon) with ESMTPS id 25c0dbd2-e4e6-11e9-9710-12813bfff9fa; Wed, 02 Oct 2019 07:27:54 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 8C7D4B0B6; Wed, 2 Oct 2019 07:27:53 +0000 (UTC) From: Juergen Gross To: xen-devel@lists.xenproject.org Date: Wed, 2 Oct 2019 09:27:44 +0200 Message-Id: <20191002072745.24919-20-jgross@suse.com> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20191002072745.24919-1-jgross@suse.com> References: <20191002072745.24919-1-jgross@suse.com> Subject: [Xen-devel] [PATCH v6 19/20] xen/sched: add scheduling granularity enum X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Juergen Gross , Stefano Stabellini , Julien Grall , Wei Liu , Konrad Rzeszutek Wilk , George Dunlap , Andrew Cooper , Ian Jackson , Tim Deegan , Jan Beulich , Dario Faggioli , =?utf-8?q?Roger_Pau_Monn=C3=A9?= MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Add a scheduling granularity enum ("cpu", "core", "socket") for specification of the scheduling granularity. Initially it is set to "cpu", this can be modified by the new boot parameter (x86 only) "sched-gran". According to the selected granularity sched_granularity is set after all cpus are online. A test is added for all sched resources holding the same number of cpus. Fall back to core- or cpu-scheduling in that case. Signed-off-by: Juergen Gross Reviewed-by: Dario Faggioli --- RFC V2: - fixed freeing of sched_res when merging cpus - rename parameter to "sched-gran" (Jan Beulich) - rename parameter option from "thread" to "cpu" (Jan Beulich) V1: - rename scheduler_smp_init() to scheduler_gran_init(), let it be called by cpupool_init() - avoid using literal cpu number 0 in scheduler_percpu_init() (Jan Beulich) - style correction (Jan Beulich) - fallback to smaller granularity instead of panic in case of unbalanced cpu configuration V2: - style changes (Jan Beulich) - introduce CONFIG_HAS_SCHED_GRANULARITY (Jan Beulich) V4: - move code to cpupool.c --- xen/arch/x86/Kconfig | 1 + xen/common/Kconfig | 3 ++ xen/common/cpupool.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 84 insertions(+) diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig index 288dc6c042..3f88adae97 100644 --- a/xen/arch/x86/Kconfig +++ b/xen/arch/x86/Kconfig @@ -22,6 +22,7 @@ config X86 select HAS_PASSTHROUGH select HAS_PCI select HAS_PDX + select HAS_SCHED_GRANULARITY select HAS_UBSAN select HAS_VPCI if !PV_SHIM_EXCLUSIVE && HVM select NEEDS_LIBELF diff --git a/xen/common/Kconfig b/xen/common/Kconfig index 16829f6274..e9247871a8 100644 --- a/xen/common/Kconfig +++ b/xen/common/Kconfig @@ -63,6 +63,9 @@ config HAS_GDBSX config HAS_IOPORTS bool +config HAS_SCHED_GRANULARITY + bool + config NEEDS_LIBELF bool diff --git a/xen/common/cpupool.c b/xen/common/cpupool.c index f7a13c7a4c..4d3adbdd8d 100644 --- a/xen/common/cpupool.c +++ b/xen/common/cpupool.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include @@ -37,6 +38,83 @@ static DEFINE_SPINLOCK(cpupool_lock); static enum sched_gran __read_mostly opt_sched_granularity = SCHED_GRAN_cpu; static unsigned int __read_mostly sched_granularity = 1; +#ifdef CONFIG_HAS_SCHED_GRANULARITY +static int __init sched_select_granularity(const char *str) +{ + if ( strcmp("cpu", str) == 0 ) + opt_sched_granularity = SCHED_GRAN_cpu; + else if ( strcmp("core", str) == 0 ) + opt_sched_granularity = SCHED_GRAN_core; + else if ( strcmp("socket", str) == 0 ) + opt_sched_granularity = SCHED_GRAN_socket; + else + return -EINVAL; + + return 0; +} +custom_param("sched-gran", sched_select_granularity); +#endif + +static unsigned int __init cpupool_check_granularity(void) +{ + unsigned int cpu; + unsigned int siblings, gran = 0; + + if ( opt_sched_granularity == SCHED_GRAN_cpu ) + return 1; + + for_each_online_cpu ( cpu ) + { + siblings = cpumask_weight(sched_get_opt_cpumask(opt_sched_granularity, + cpu)); + if ( gran == 0 ) + gran = siblings; + else if ( gran != siblings ) + return 0; + } + + sched_disable_smt_switching = true; + + return gran; +} + +/* Setup data for selected scheduler granularity. */ +static void __init cpupool_gran_init(void) +{ + unsigned int gran = 0; + const char *fallback = NULL; + + while ( gran == 0 ) + { + gran = cpupool_check_granularity(); + + if ( gran == 0 ) + { + switch ( opt_sched_granularity ) + { + case SCHED_GRAN_core: + opt_sched_granularity = SCHED_GRAN_cpu; + fallback = "Asymmetric cpu configuration.\n" + "Falling back to sched-gran=cpu.\n"; + break; + case SCHED_GRAN_socket: + opt_sched_granularity = SCHED_GRAN_core; + fallback = "Asymmetric cpu configuration.\n" + "Falling back to sched-gran=core.\n"; + break; + default: + ASSERT_UNREACHABLE(); + break; + } + } + } + + if ( fallback ) + warning_add(fallback); + + sched_granularity = gran; +} + unsigned int cpupool_get_granularity(const struct cpupool *c) { return c ? sched_granularity : 1; @@ -871,6 +949,8 @@ static int __init cpupool_init(void) unsigned int cpu; int err; + cpupool_gran_init(); + cpupool0 = cpupool_create(0, 0, &err); BUG_ON(cpupool0 == NULL); cpupool_put(cpupool0);