[U-Boot] usb_test_unit_ready called every block read - performance

Marek Vasut marex at denx.de
Mon Aug 13 01:54:29 CEST 2012


Dear Jim Shimer,

> While tuning ext2load, we found that usb_test_unit_ready was being called
> every block read.  We compared the usb block storage to the scsi block
> storage cmd_scsi.c, and found that the scsi device was only calling its
> scsi_setup_test_unit_ready() during scsi_can.  It appears that
> usb_test_unit_ready() really only needs to be called once during
> usb_stor_scan(), via usb_stor_get_info().   Is there a particular reason
> usb_test_unit_ready is called for every block read, or do you think its ok
> to only call during usb_stor_scan()?  We're finding this speeds up ext2load
> quite a bit.

Jim, did we get anywhere on this one ? Can you try with the new ext4 code in 
Wolfgangs' u-boot-master/ext4 branch?

> Regards,
> Jim

Best regards,
Marek Vasut


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