Acked-by: Brian King <brking@xxxxxxxxxxxxxxxxxx>
On 05/19/2010 01:56 PM, Wayne Boyer wrote:
> 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 <wayneb@xxxxxxxxxxxxxxxxxx>
> ---
>
> 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;
>
> --
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--
Brian King
Linux on Power Virtualization
IBM Linux Technology Center
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