ahci: enable full queue depth of 32

This changes the AHCI queue depth from 31 to 32, as libata now
fully supports it. Now regular IO requests can utilize the full
tag space of SATA, not just 31. For IOPS constrained workloads,
this can result in a ~3% bump in performance.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 824bd399f02ea4b350a85d004d2c3fefdf39d0ff..1609ebab4e230e885040a0b4582c4b09c789fa7f 100644 (file)
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -390,7 +390,7 @@ extern struct device_attribute *ahci_sdev_attrs[];
  */
 #define AHCI_SHT(drv_name)                                             \
        ATA_NCQ_SHT(drv_name),                                          \
-       .can_queue              = AHCI_MAX_CMDS - 1,                    \
+       .can_queue              = AHCI_MAX_CMDS,                        \
        .sg_tablesize           = AHCI_MAX_SG,                          \
        .dma_boundary           = AHCI_DMA_BOUNDARY,                    \
        .shost_attrs            = ahci_shost_attrs,                     \