From nobody Tue Feb 10 07:44:23 2026 Delivered-To: importer@patchew.org Received-SPF: none (zoho.com: 192.237.175.120 is neither permitted nor denied by domain of lists.xenproject.org) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; spf=none (zoho.com: 192.237.175.120 is neither permitted nor denied by domain of lists.xenproject.org) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org ARC-Seal: i=1; a=rsa-sha256; t=1559039738; cv=none; d=zoho.com; s=zohoarc; b=oEGjaFWKManNI2/PfTnqj/Gf1d5k1WuxzpuPeQSVgNicC1TUi131+JzM10fbej4E6GNLj/3dHzqfCLqdp3qWCOcM8En01EF8LibnEOMJVnkPpnz4s6uigFUKiDHm1E1y65slyjovjf85BG7YdsM1n6vfVYezxFxcoalj2MOzVP0= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1559039738; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To:ARC-Authentication-Results; bh=gpjcloHLeNq1tyiybOiVgiIwDO871mQcPtDq/LRhJps=; b=K3prkBDzdI3mrrPr5Y/eYydfMp8knl71hZMKktYyOkQ24D1hLO7oz5eVGQiwLYpjB0ckKhYCfADbGvm/KkEfBxNS04CjSl2+JiFxgGfNFIhrYtJsdsNrSAZpggrraii58IJLGEkASbQ9xr7oCW7feEFBN4qnHFWLUTPoHSANuoY= ARC-Authentication-Results: i=1; mx.zoho.com; spf=none (zoho.com: 192.237.175.120 is neither permitted nor denied by domain of lists.xenproject.org) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 155903973819397.29837219229046; Tue, 28 May 2019 03:35:38 -0700 (PDT) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hVZRV-0007hs-LH; Tue, 28 May 2019 10:34:53 +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 1hVZQJ-00053Z-A7 for xen-devel@lists.xenproject.org; Tue, 28 May 2019 10:33:39 +0000 Received: from mx1.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 0a641504-8134-11e9-ae0e-4b41fbb2c99e; Tue, 28 May 2019 10:33:32 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 277F1B0B3; Tue, 28 May 2019 10:33:32 +0000 (UTC) X-Inumbo-ID: 0a641504-8134-11e9-ae0e-4b41fbb2c99e X-Virus-Scanned: by amavisd-new at test-mx.suse.de From: Juergen Gross To: xen-devel@lists.xenproject.org Date: Tue, 28 May 2019 12:33:13 +0200 Message-Id: <20190528103313.1343-61-jgross@suse.com> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20190528103313.1343-1-jgross@suse.com> References: <20190528103313.1343-1-jgross@suse.com> Subject: [Xen-devel] [PATCH 60/60] 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 , Tim Deegan , Stefano Stabellini , Wei Liu , Konrad Rzeszutek Wilk , George Dunlap , Andrew Cooper , Ian Jackson , Dario Faggioli , Julien Grall , Jan Beulich MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable 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 --- 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 --- xen/common/cpupool.c | 2 ++ xen/common/schedule.c | 78 ++++++++++++++++++++++++++++++++++++++++++= ++++ xen/include/xen/sched-if.h | 1 + 3 files changed, 81 insertions(+) diff --git a/xen/common/cpupool.c b/xen/common/cpupool.c index 4dac7dedca..5a01f90d08 100644 --- a/xen/common/cpupool.c +++ b/xen/common/cpupool.c @@ -868,6 +868,8 @@ static int __init cpupool_init(void) unsigned int cpu; int err; =20 + scheduler_gran_init(); + cpupool0 =3D cpupool_create(0, 0, &err); BUG_ON(cpupool0 =3D=3D NULL); cpupool_put(cpupool0); diff --git a/xen/common/schedule.c b/xen/common/schedule.c index fed71b26d2..9e9b7f5f48 100644 --- a/xen/common/schedule.c +++ b/xen/common/schedule.c @@ -34,6 +34,7 @@ #include #include #include +#include #include #include #include @@ -61,6 +62,23 @@ unsigned int sched_granularity =3D 1; bool sched_disable_smt_switching; cpumask_var_t sched_res_mask; =20 +#ifdef CONFIG_X86 +static int __init sched_select_granularity(const char *str) +{ + if (strcmp("cpu", str) =3D=3D 0) + opt_sched_granularity =3D SCHED_GRAN_cpu; + else if (strcmp("core", str) =3D=3D 0) + opt_sched_granularity =3D SCHED_GRAN_core; + else if (strcmp("socket", str) =3D=3D 0) + opt_sched_granularity =3D SCHED_GRAN_socket; + else + return -EINVAL; + + return 0; +} +custom_param("sched-gran", sched_select_granularity); +#endif + /* Common lock for free cpus. */ static DEFINE_SPINLOCK(sched_free_cpu_lock); =20 @@ -2492,6 +2510,66 @@ const cpumask_t *sched_get_opt_cpumask(enum sched_gr= an opt, unsigned int cpu) return mask; } =20 +static unsigned int __init sched_check_granularity(void) +{ + unsigned int cpu; + unsigned int siblings, gran =3D 0; + + if ( opt_sched_granularity =3D=3D SCHED_GRAN_cpu ) + return 1; + + for_each_online_cpu ( cpu ) + { + siblings =3D cpumask_weight(sched_get_opt_cpumask(opt_sched_granul= arity, + cpu)); + if ( gran =3D=3D 0 ) + gran =3D siblings; + else if ( gran !=3D siblings ) + return 0; + } + + sched_disable_smt_switching =3D true; + + return gran; +} + +/* Setup data for selected scheduler granularity. */ +void __init scheduler_gran_init(void) +{ + unsigned int gran =3D 0; + const char *fallback =3D NULL; + + while ( gran =3D=3D 0 ) + { + gran =3D sched_check_granularity(); + + if ( gran =3D=3D 0 ) + { + switch ( opt_sched_granularity ) + { + case SCHED_GRAN_core: + opt_sched_granularity =3D SCHED_GRAN_cpu; + fallback =3D "Asymmetric cpu configuration.\n" + "Falling back to sched-gran=3Dcpu.\n"; + break; + case SCHED_GRAN_socket: + opt_sched_granularity =3D SCHED_GRAN_core; + fallback =3D "Asymmetric cpu configuration.\n" + "Falling back to sched-gran=3Dcore.\n"; + break; + default: + ASSERT_UNREACHABLE(); + break; + } + } + } + + if ( fallback ) + warning_add(fallback); + + sched_granularity =3D gran; +} + /* Initialise the data structures. */ void __init scheduler_init(void) { diff --git a/xen/include/xen/sched-if.h b/xen/include/xen/sched-if.h index c125236068..e16884fdf5 100644 --- a/xen/include/xen/sched-if.h +++ b/xen/include/xen/sched-if.h @@ -614,5 +614,6 @@ affinity_balance_cpumask(const struct sched_unit *unit,= int step, =20 void sched_rm_cpu(unsigned int cpu); const cpumask_t *sched_get_opt_cpumask(enum sched_gran opt, unsigned int c= pu); +void scheduler_gran_init(void); =20 #endif /* __XEN_SCHED_IF_H__ */ --=20 2.16.4 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel