Re: (2.6.0-test9) usb_storage/uhci_hcd much slower write than linux-2.4

[Tim Shepard]

Someone sent me a private e-mail message suggesting that I apply this
patch that Matthew Dharm posted to the linux-usb-devel list yesterday
and see if that would restore the write throughput to linux-2.4
levels.

The patch limits the size of the transfers, and can be found at 

	http://sourceforge.net/mailarchive/message.php?msg_id=6429200

or right here:

--- drivers/usb/storage/scsiglue.c.orig	2003-08-09 00:36:46.000000000 -0400
+++ drivers/usb/storage/scsiglue.c	2003-11-03 16:49:42.000000000 -0500
@@ -315,6 +315,9 @@
 	/* lots of sg segments can be handled */
 	.sg_tablesize =			SG_ALL,
 
+	/* limit the total size of a transfer to 120 KB */
+	.max_sectors =			240,
+
 	/* merge commands... this seems to help performance, but
 	 * periodically someone should test to see which setting is more
 	 * optimal.


I am happy to report that this patch has restored the write throughput
to the same speed that it was on linux-2.4.

Problem solved.    Thanks much.

			-Tim Shepard
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/