From patchwork Fri Oct 30 21:09:46 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 538524 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id AB932140323 for ; Sat, 31 Oct 2015 08:15:29 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030428AbbJ3VP3 (ORCPT ); Fri, 30 Oct 2015 17:15:29 -0400 Received: from mga09.intel.com ([134.134.136.24]:4784 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030348AbbJ3VP2 (ORCPT ); Fri, 30 Oct 2015 17:15:28 -0400 Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga102.jf.intel.com with ESMTP; 30 Oct 2015 14:15:28 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,220,1444719600"; d="scan'208";a="839619777" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.39]) by fmsmga002.fm.intel.com with ESMTP; 30 Oct 2015 14:15:28 -0700 Subject: [PATCH 4/4] ahci: switch from 'threaded' to 'hardirq' interrupt handling From: Dan Williams To: tj@kernel.org Cc: linux-ide@vger.kernel.org Date: Fri, 30 Oct 2015 17:09:46 -0400 Message-ID: <20151030210946.8538.26203.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <20151030210924.8538.90627.stgit@dwillia2-desk3.amr.corp.intel.com> References: <20151030210924.8538.90627.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 Sender: linux-ide-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ide@vger.kernel.org For high frequency I/O the overhead of threaded interrupts impacts performance. Add an option to make it configurable, with the default being hardirq. A quick out-of-the-box test (i.e. no affinity tuning) shows ~10% random read performance at ~20% less cpu. The cpu wins appear to be from reduced lock contention. Signed-off-by: Dan Williams --- drivers/ata/libahci.c | 38 ++++++++++++++++++++++++++++++++++---- 1 file changed, 34 insertions(+), 4 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c index c6f098a0435c..69bbd679d6aa 100644 --- a/drivers/ata/libahci.c +++ b/drivers/ata/libahci.c @@ -57,6 +57,10 @@ MODULE_PARM_DESC(skip_host_reset, "skip global host reset (0=don't skip, 1=skip) module_param_named(ignore_sss, ahci_ignore_sss, int, 0444); MODULE_PARM_DESC(ignore_sss, "Ignore staggered spinup flag (0=don't ignore, 1=ignore)"); +static int use_threaded_interrupts; +module_param(use_threaded_interrupts, int, 0444); +MODULE_PARM_DESC(, "Defer interrupt handling to a thread (0=don't defer, 1=defer)"); + static int ahci_set_lpm(struct ata_link *link, enum ata_lpm_policy policy, unsigned hints); static ssize_t ahci_led_show(struct ata_port *ap, char *buf); @@ -1826,6 +1830,26 @@ static irqreturn_t ahci_multi_irqs_intr(int irq, void *dev_instance) return IRQ_WAKE_THREAD; } +static irqreturn_t ahci_multi_irqs_intr_hard(int irq, void *dev_instance) +{ + struct ata_port *ap = dev_instance; + void __iomem *port_mmio = ahci_port_base(ap); + u32 status; + + VPRINTK("ENTER\n"); + + status = readl(port_mmio + PORT_IRQ_STAT); + writel(status, port_mmio + PORT_IRQ_STAT); + + spin_lock(ap->lock); + ahci_handle_port_interrupt(ap, port_mmio, status); + spin_unlock(ap->lock); + + VPRINTK("EXIT\n"); + + return IRQ_HANDLED; +} + static u32 ahci_handle_port_intr(struct ata_host *host, u32 irq_masked) { unsigned int i, handled = 0; @@ -2492,10 +2516,16 @@ static int ahci_host_activate_multi_irqs(struct ata_host *host, continue; } - rc = devm_request_threaded_irq(host->dev, irq, - ahci_multi_irqs_intr, - ahci_port_thread_fn, 0, - pp->irq_desc, host->ports[i]); + if (use_threaded_interrupts) + rc = devm_request_threaded_irq(host->dev, irq, + ahci_multi_irqs_intr, + ahci_port_thread_fn, 0, + pp->irq_desc, host->ports[i]); + else + rc = devm_request_irq(host->dev, irq, + ahci_multi_irqs_intr_hard, 0, + pp->irq_desc, host->ports[i]); + if (rc) return rc; ata_port_desc(host->ports[i], "irq %d", irq);