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| author | Dan Williams <dan.j.williams@intel.com> | 2015-11-11 16:27:38 -0800 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2015-11-16 11:29:10 -0500 |
| commit | a6b7fb764ed2a6b7bb1ac96d93c06787aa589092 (patch) | |
| tree | 02bd0d5a1aa33e2fa3cb509ca4607b9ff11558bc /drivers/ata | |
| parent | d684a90d38e24dcaf95fdb32c83efe05f80d152a (diff) | |
| download | linux-a6b7fb764ed2a6b7bb1ac96d93c06787aa589092.tar.gz linux-a6b7fb764ed2a6b7bb1ac96d93c06787aa589092.tar.bz2 linux-a6b7fb764ed2a6b7bb1ac96d93c06787aa589092.zip | |
ahci: switch from 'threaded' to 'hardirq' interrupt handling
For high frequency I/O the overhead of threaded interrupts impacts
performance. 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 <dan.j.williams@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'drivers/ata')
| -rw-r--r-- | drivers/ata/libahci.c | 34 |
1 files changed, 8 insertions, 26 deletions
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c index 0a5645fb02f8..1b6c7cc415bf 100644 --- a/drivers/ata/libahci.c +++ b/drivers/ata/libahci.c @@ -1796,41 +1796,24 @@ static void ahci_port_intr(struct ata_port *ap) ahci_handle_port_interrupt(ap, port_mmio, status); } -static irqreturn_t ahci_port_thread_fn(int irq, void *dev_instance) +static irqreturn_t ahci_multi_irqs_intr_hard(int irq, void *dev_instance) { struct ata_port *ap = dev_instance; - struct ahci_port_priv *pp = ap->private_data; void __iomem *port_mmio = ahci_port_base(ap); u32 status; - status = atomic_xchg(&pp->intr_status, 0); - if (!status) - return IRQ_NONE; - - spin_lock_bh(ap->lock); - ahci_handle_port_interrupt(ap, port_mmio, status); - spin_unlock_bh(ap->lock); - - return IRQ_HANDLED; -} - -static irqreturn_t ahci_multi_irqs_intr(int irq, void *dev_instance) -{ - struct ata_port *ap = dev_instance; - void __iomem *port_mmio = ahci_port_base(ap); - struct ahci_port_priv *pp = ap->private_data; - u32 status; - VPRINTK("ENTER\n"); status = readl(port_mmio + PORT_IRQ_STAT); writel(status, port_mmio + PORT_IRQ_STAT); - atomic_or(status, &pp->intr_status); + spin_lock(ap->lock); + ahci_handle_port_interrupt(ap, port_mmio, status); + spin_unlock(ap->lock); VPRINTK("EXIT\n"); - return IRQ_WAKE_THREAD; + return IRQ_HANDLED; } static u32 ahci_handle_port_intr(struct ata_host *host, u32 irq_masked) @@ -2499,10 +2482,9 @@ 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]); + 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); |