From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wayne Boyer Subject: [PATCH 1/1] ipr: improve interrupt service routine performance Date: Wed, 19 May 2010 11:56:13 -0700 Message-ID: <4BF4344D.6070109@linux.vnet.ibm.com> References: <20100519184827.824039221@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from e39.co.us.ibm.com ([32.97.110.160]:46481 "EHLO e39.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751238Ab0ESS41 (ORCPT ); Wed, 19 May 2010 14:56:27 -0400 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e39.co.us.ibm.com (8.14.3/8.13.1) with ESMTP id o4JIldhc021583 for ; Wed, 19 May 2010 12:47:39 -0600 Received: from d03av06.boulder.ibm.com (d03av06.boulder.ibm.com [9.17.195.245]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id o4JIuHK7236210 for ; Wed, 19 May 2010 12:56:21 -0600 Received: from d03av06.boulder.ibm.com (loopback [127.0.0.1]) by d03av06.boulder.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o4JIx9RN023745 for ; Wed, 19 May 2010 12:59:09 -0600 In-Reply-To: <20100519184827.824039221@linux.vnet.ibm.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: linux-scsi , Brian King During performance testing on P7 machines it was observed that the interrupt service routine was doing unnecessary MMIO operations. This patch rearranges the logic of the routine and moves some of the code out of the main routine. The result is that there are now fewer MMIO operations in the performance path of the code. Signed-off-by: Wayne Boyer --- drivers/scsi/ipr.c | 63 +++++++++++++++++++++++++---------------------------- 1 file changed, 30 insertions(+), 33 deletions(-) Index: b/drivers/scsi/ipr.c =================================================================== --- a/drivers/scsi/ipr.c 2010-05-18 09:17:00.000000000 -0700 +++ b/drivers/scsi/ipr.c 2010-05-19 11:44:18.000000000 -0700 @@ -4815,15 +4815,39 @@ static int ipr_eh_abort(struct scsi_cmnd /** * ipr_handle_other_interrupt - Handle "other" interrupts * @ioa_cfg: ioa config struct - * @int_reg: interrupt register * * Return value: * IRQ_NONE / IRQ_HANDLED **/ -static irqreturn_t ipr_handle_other_interrupt(struct ipr_ioa_cfg *ioa_cfg, - volatile u32 int_reg) +static irqreturn_t ipr_handle_other_interrupt(struct ipr_ioa_cfg *ioa_cfg) { irqreturn_t rc = IRQ_HANDLED; + volatile u32 int_reg, int_mask_reg; + + int_mask_reg = readl(ioa_cfg->regs.sense_interrupt_mask_reg32); + int_reg = readl(ioa_cfg->regs.sense_interrupt_reg32) & ~int_mask_reg; + + /* If an interrupt on the adapter did not occur, ignore it. + * Or in the case of SIS 64, check for a stage change interrupt. + */ + if ((int_reg & IPR_PCII_OPER_INTERRUPTS) == 0) { + if (ioa_cfg->sis64) { + int_mask_reg = readl(ioa_cfg->regs.sense_interrupt_mask_reg); + int_reg = readl(ioa_cfg->regs.sense_interrupt_reg) & ~int_mask_reg; + if (int_reg & IPR_PCII_IPL_STAGE_CHANGE) { + + /* clear stage change */ + writel(IPR_PCII_IPL_STAGE_CHANGE, ioa_cfg->regs.clr_interrupt_reg); + int_reg = readl(ioa_cfg->regs.sense_interrupt_reg) & ~int_mask_reg; + list_del(&ioa_cfg->reset_cmd->queue); + del_timer(&ioa_cfg->reset_cmd->timer); + ipr_reset_ioa_job(ioa_cfg->reset_cmd); + return IRQ_HANDLED; + } + } + + return IRQ_NONE; + } if (int_reg & IPR_PCII_IOA_TRANS_TO_OPER) { /* Mask the interrupt */ @@ -4884,7 +4908,7 @@ static irqreturn_t ipr_isr(int irq, void { struct ipr_ioa_cfg *ioa_cfg = (struct ipr_ioa_cfg *)devp; unsigned long lock_flags = 0; - volatile u32 int_reg, int_mask_reg; + volatile u32 int_reg; u32 ioasc; u16 cmd_index; int num_hrrq = 0; @@ -4899,33 +4923,6 @@ static irqreturn_t ipr_isr(int irq, void return IRQ_NONE; } - int_mask_reg = readl(ioa_cfg->regs.sense_interrupt_mask_reg32); - int_reg = readl(ioa_cfg->regs.sense_interrupt_reg32) & ~int_mask_reg; - - /* If an interrupt on the adapter did not occur, ignore it. - * Or in the case of SIS 64, check for a stage change interrupt. - */ - if (unlikely((int_reg & IPR_PCII_OPER_INTERRUPTS) == 0)) { - if (ioa_cfg->sis64) { - int_mask_reg = readl(ioa_cfg->regs.sense_interrupt_mask_reg); - int_reg = readl(ioa_cfg->regs.sense_interrupt_reg) & ~int_mask_reg; - if (int_reg & IPR_PCII_IPL_STAGE_CHANGE) { - - /* clear stage change */ - writel(IPR_PCII_IPL_STAGE_CHANGE, ioa_cfg->regs.clr_interrupt_reg); - int_reg = readl(ioa_cfg->regs.sense_interrupt_reg) & ~int_mask_reg; - list_del(&ioa_cfg->reset_cmd->queue); - del_timer(&ioa_cfg->reset_cmd->timer); - ipr_reset_ioa_job(ioa_cfg->reset_cmd); - spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags); - return IRQ_HANDLED; - } - } - - spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags); - return IRQ_NONE; - } - while (1) { ipr_cmd = NULL; @@ -4965,7 +4962,7 @@ static irqreturn_t ipr_isr(int irq, void /* Clear the PCI interrupt */ do { writel(IPR_PCII_HRRQ_UPDATED, ioa_cfg->regs.clr_interrupt_reg32); - int_reg = readl(ioa_cfg->regs.sense_interrupt_reg32) & ~int_mask_reg; + int_reg = readl(ioa_cfg->regs.sense_interrupt_reg32); } while (int_reg & IPR_PCII_HRRQ_UPDATED && num_hrrq++ < IPR_MAX_HRRQ_RETRIES); @@ -4980,7 +4977,7 @@ static irqreturn_t ipr_isr(int irq, void } if (unlikely(rc == IRQ_NONE)) - rc = ipr_handle_other_interrupt(ioa_cfg, int_reg); + rc = ipr_handle_other_interrupt(ioa_cfg); spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags); return rc;