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

From: Tim Shepard
Date: Mon Nov 03 2003 - 17:18:37 EST

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

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

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
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