FIXED: mpt Serious performance issues

[Stephan <stephanwib%googlemail.com@localhost>]

Have a look at these values:

====================

find / -exec cat {} \; > /dev/null

Disks:   fd0   cd0   sd0   md0
 seeks
 xfers              1085
 bytes               68M
 %busy              92.4

====================

bsddev# dd if=/dev/zero of=myfile bs=4096 count=100000
100000+0 records in
100000+0 records out
409600000 bytes transferred in 6.516 secs (62860650 bytes/sec)
bsddev# ls -lh myfile
-rw-r--r--  1 root  wheel  391M Feb  4 15:28 myfile

===================

This is approx. the maximum performance of the old hardware.

So what is wrong with the driver? There are 16 pages represented by
fCONFIG_PAGE_SCSI_DEVICE_1 available in the controller and every
single page represents one *PHYSICAL* SCSI target. For example, in
mpt_set_xfer_mode(), such a page is assembled with the requested modes
and then trasferred to the controller via mpt_write_cfg_page(). When
the computer starts, the LSI Firmware BIOS scans the disks and sets a
meaningful initial setup for each of them. The debugging code shows
that on NetBSD boot (2 disks were inserted):

Feb  4 14:19:30 bsddev /netbsd: mpt0: SPI Tgt 0 Page 0: NParms
201f08c7 Information 1
Feb  4 14:19:30 bsddev /netbsd: mpt0: SPI Tgt 0 Page 1: RParms
201f0807 Configuration 0
Feb  4 14:19:30 bsddev /netbsd: mpt0: SPI Tgt 1 Page 0: NParms
201f08c7 Information 1
Feb  4 14:19:30 bsddev /netbsd: mpt0: SPI Tgt 1 Page 1: RParms
201f0807 Configuration 0
Feb  4 14:19:30 bsddev /netbsd: mpt0: SPI Tgt 2 Page 0: NParms 0 Information 0
Feb  4 14:19:30 bsddev /netbsd: mpt0: SPI Tgt 2 Page 1: RParms 0 Configuration 6
...

What then happens is very stupid. The driver calls
mpt_set_initial_config() in mpt.c which resets every 16 target device
pages to 0:

Feb  4 14:19:30 bsddev /netbsd: mpt0: Set Tgt 0 SPI DevicePage 1 values to 0 0 0
Feb  4 14:19:30 bsddev /netbsd: mpt0: SPI Tgt 0 Page 1: RParm 0 Configuration 0
Feb  4 14:19:30 bsddev /netbsd: mpt0: Set Tgt 1 SPI DevicePage 1 values to 0 0 0
Feb  4 14:19:30 bsddev /netbsd: mpt0: SPI Tgt 1 Page 1: RParm 0 Configuration 0
Feb  4 14:19:30 bsddev /netbsd: mpt0: Set Tgt 2 SPI DevicePage 1 values to 0 0 0
Feb  4 14:19:30 bsddev /netbsd: mpt0: SPI Tgt 2 Page 1: RParm 0 Configuration 0
...

Now every physical disk, being part of a RAID array or not, runs in a
prehistoric mode. When the scsipi layer then scans the bus and detects
the virtual target (sd0), the target device page for disk 0 again gets
initialized with useful values (this is the fast, lower disk) but the
page for disk 1 obviously not (this is the slow, upper disk). A simple
but useful solution seems to be the removal of the code which clears
all of the target pages as they were initialized correctly by the
Firmware BIOS. A patch is attached. Comments? Is this good for
commitment?

======================================
--- /usr/src/sys/dev/ic/mpt.c   2007-07-27 20:38:13.000000000 +0200
+++ mpt.c       2011-02-04 12:54:17.000000000 +0100
@@ -863,7 +863,7 @@
 static int
 mpt_set_initial_config_spi(mpt_softc_t *mpt)
 {
-       int i, pp1val = ((1 << mpt->mpt_ini_id) << 16) | mpt->mpt_ini_id;
+       int pp1val = ((1 << mpt->mpt_ini_id) << 16) | mpt->mpt_ini_id;

        mpt->mpt_disc_enable = 0xff;
        mpt->mpt_tag_enable = 0;
@@ -888,31 +888,6 @@
                }
                mpt->mpt_port_page1 = tmp;
        }
-
-       for (i = 0; i < 16; i++) {
-               fCONFIG_PAGE_SCSI_DEVICE_1 tmp;
-               tmp = mpt->mpt_dev_page1[i];
-               tmp.RequestedParameters = 0;
-               tmp.Configuration = 0;
-               if (mpt->verbose > 1) {
-                       mpt_prt(mpt,
-                           "Set Tgt %d SPI DevicePage 1 values to %x 0 %x",
-                           i, tmp.RequestedParameters, tmp.Configuration);
-               }
-               if (mpt_write_cfg_page(mpt, i, &tmp.Header)) {
-                       return (-1);
-               }
-               if (mpt_read_cfg_page(mpt, i, &tmp.Header)) {
-                       return (-1);
-               }
-               mpt->mpt_dev_page1[i] = tmp;
-               if (mpt->verbose > 1) {
-                       mpt_prt(mpt,
-                           "SPI Tgt %d Page 1: RParm %x Configuration %x", i,
-                           mpt->mpt_dev_page1[i].RequestedParameters,
-                           mpt->mpt_dev_page1[i].Configuration);
-               }
-       }
        return (0);
 }