On Mon, 21 Mar 2005, Andrew Morton wrote:
> Holger, this problem remains unresolved, does it not? Have you done any
> more experimentation?
>
> I must say that something funny seems to be happening here. I have two
> MPT-based Dell machines, neither of which is using a modular driver:
>
> akpm:/usr/src/25> 0 hdparm -t /dev/sda
>
> /dev/sda:
> Timing buffered disk reads: 64 MB in 5.00 seconds = 12.80 MB/sec
Holger Kiehl wrote on Tuesday, March 22, 2005 12:31 AM
> Got the same result when compiled in, always between 12 and 13 MB/s. As
> module it is approx. 75 MB/s.
Half guess, half with data to prove: it must be the variable driver_setup
initialization. If compiled as built-in, driver_setup is initialized to
zero for all of its member variables, which isn't the fastest setting. If
compiled as module, it gets first class treatment with shinny performance
setting. Goofing around, this patch appears to be giving higher throughput.
Before:
/dev/sdc:
Timing buffered disk reads: 92 MB in 3.03 seconds = 30.32 MB/sec
After:
/dev/sdc:
Timing buffered disk reads: 174 MB in 3.02 seconds = 57.61 MB/sec
diff -Nurp linux-2.6.11/drivers/message/fusion/mptscsih.c
linux-2.6.11.ken/drivers/message/fusion/mptscsih.c
--- linux-2.6.11/drivers/message/fusion/mptscsih.c 2005-03-01
23:38:37.000000000 -0800
+++ linux-2.6.11.ken/drivers/message/fusion/mptscsih.c 2005-03-22
02:18:21.000000000 -0800
@@ -96,7 +96,6 @@ MODULE_AUTHOR(MODULEAUTHOR);
MODULE_DESCRIPTION(my_NAME);
MODULE_LICENSE("GPL");
-#ifdef MODULE
static int dv = MPTSCSIH_DOMAIN_VALIDATION;
module_param(dv, int, 0);
MODULE_PARM_DESC(dv, "DV Algorithm: enhanced = 1, basic = 0
(default=MPTSCSIH_DOMAIN_VALIDATION=1)");
@@ -112,7 +111,6 @@ MODULE_PARM_DESC(factor, "Min Sync Facto
static int saf_te = MPTSCSIH_SAF_TE;
module_param(saf_te, int, 0);
MODULE_PARM_DESC(saf_te, "Force enabling SEP Processor:
(default=MPTSCSIH_SAF_TE=0)");
-#endif
/*=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=*/
@@ -1489,7 +1487,6 @@ mptscsih_init(void)
": Registered for IOC reset notifications\n"));
}
-#ifdef MODULE
dinitprintk((KERN_INFO MYNAM
": Command Line Args: dv=%d max_width=%d "
"factor=0x%x saf_te=%d\n",
@@ -1499,7 +1496,6 @@ mptscsih_init(void)
driver_setup.max_width = (width) ? 1 : 0;
driver_setup.min_sync_factor = factor;
driver_setup.saf_te = (saf_te) ? 1 : 0;;
-#endif
if(mpt_device_driver_register(&mptscsih_driver,
MPTSCSIH_DRIVER) != 0 ) {
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
