scsi: esp_scsi: Optimize PIO loops

Avoid function calls in the inner PIO loops. On a Centris 660av this
improves throughput for sequential read transfers by about 40% and
sequential write by about 10%.

Unfortunately it is not possible to have methods like .esp_write8 placed
inline so this is always going to be slow, even with LTO.

Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/esp_scsi.c b/drivers/scsi/esp_scsi.c
index a167f70..ac7da9d 100644 (file)
--- a/drivers/scsi/esp_scsi.c
+++ b/drivers/scsi/esp_scsi.c
@@ -2794,7 +2794,7 @@ static inline unsigned int esp_wait_for_fifo(struct esp *esp)
                if (fbytes)
                        return fbytes;
 
-               udelay(2);
+               udelay(1);
        } while (--i);
 
        shost_printk(KERN_ERR, esp->host, "FIFO is empty. sreg [%02x]\n",
@@ -2811,7 +2811,7 @@ static inline int esp_wait_for_intr(struct esp *esp)
                if (esp->sreg & ESP_STAT_INTR)
                        return 0;
 
-               udelay(2);
+               udelay(1);
        } while (--i);
 
        shost_printk(KERN_ERR, esp->host, "IRQ timeout. sreg [%02x]\n",
@@ -2839,7 +2839,7 @@ void esp_send_pio_cmd(struct esp *esp, u32 addr, u32 esp_count,
                        if (!esp_wait_for_fifo(esp))
                                break;
 
-                       *dst++ = esp_read8(ESP_FDATA);
+                       *dst++ = readb(esp->fifo_reg);
                        --esp_count;
 
                        if (!esp_count)
@@ -2860,9 +2860,9 @@ void esp_send_pio_cmd(struct esp *esp, u32 addr, u32 esp_count,
                        }
 
                        if (phase == ESP_MIP)
-                               scsi_esp_cmd(esp, ESP_CMD_MOK);
+                               esp_write8(ESP_CMD_MOK, ESP_CMD);
 
-                       scsi_esp_cmd(esp, ESP_CMD_TI);
+                       esp_write8(ESP_CMD_TI, ESP_CMD);
                }
        } else {
                unsigned int n = ESP_FIFO_SIZE;
@@ -2902,7 +2902,7 @@ void esp_send_pio_cmd(struct esp *esp, u32 addr, u32 esp_count,
                        src += n;
                        esp_count -= n;
 
-                       scsi_esp_cmd(esp, ESP_CMD_TI);
+                       esp_write8(ESP_CMD_TI, ESP_CMD);
                }
        }