On Sat, 13 Oct 2018, Michael Schmitz wrote:
> Hi Finn,
>
> Am 13.10.2018 um 13:51 schrieb Finn Thain:
> > 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 method calls like esp_write8()
> > placed inline so this is always going to be slow (even with LTO).
> >
> > Tested-by: Stan Johnson <userm57@xxxxxxxxx>
> > Signed-off-by: Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx>
> > ---
> > drivers/scsi/esp_scsi.c | 14 +++++++-------
> > 1 file changed, 7 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/scsi/esp_scsi.c b/drivers/scsi/esp_scsi.c
> > index 646701fc22a4..9f0e68cd0e99 100644
> > --- a/drivers/scsi/esp_scsi.c
> > +++ b/drivers/scsi/esp_scsi.c
> > @@ -2788,7 +2788,7 @@ static inline unsigned int esp_wait_for_fifo(struct
> > esp *esp)
> > if (fbytes)
> > return fbytes;
> >
> > - udelay(2);
> > + udelay(1);
> > } while (--i);
> >
> > pr_err("FIFO is empty (sreg %02x)\n", esp_read8(ESP_STATUS));
> > @@ -2804,7 +2804,7 @@ static inline int esp_wait_for_intr(struct esp *esp)
> > if (esp->sreg & ESP_STAT_INTR)
> > return 0;
> >
> > - udelay(2);
> > + udelay(1);
> > } while (--i);
> >
> > pr_err("IRQ timeout (sreg %02x)\n", esp->sreg);
> > @@ -2831,7 +2831,7 @@ 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)
> > @@ -2852,15 +2852,15 @@ 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);
>
> You're no longer logging this command with this patch. (That'll be the reason
> for the speedup you saw ...)
>
> >
> > - scsi_esp_cmd(esp, ESP_CMD_TI);
> > + esp_write8(ESP_CMD_TI, ESP_CMD);
>
> Same here..
>
> > }
> > } else {
> > unsigned int n = ESP_FIFO_SIZE;
> > u8 *src = (u8 *)addr;
> >
> > - scsi_esp_cmd(esp, ESP_CMD_FLUSH);
> > + esp_write8(ESP_CMD_FLUSH, ESP_CMD);
>
> here..
>
> >
> > if (n > esp_count)
> > n = esp_count;
> > @@ -2894,7 +2894,7 @@ 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);
>
> and here.
>
Yes, it's deliberate.
> The burst of ESP_CMD_TI's in the log was quite useful to spot what went
> wrong during PIO.
I don't think it's as useful as you seem to think. Compare
mac_esp_send_pdma_cmd().
> Maybe mention in the changelog that commands during PIO are no longer
> logged? Or introduce a new ESP_EVENT_PIO and log that at the start of
> PIO?
>
Yes, and I did leave a scsi_esp_cmd(esp, cmd) call at the start of PIO.
That should be sufficient, right?
--
> Cheers,
>
> Michael
>
>
>
> > }
> > }
> >
> >
>
