Hi, i had found a problem with CONFIG_SCSI_MQ_DEFAULT config option. If it activated, then the write speeds to the /dev/sd* of an usb stick drops dramatically: it's only about 250 kb/CONFIG_SCSI_MQ_DEFAULTs, but should be about 7 Mb/s. Git bisect also points to commit 24c20f10583647e30afe87b6f6d5e14bc7b1cbc6 'scsi: add a CONFIG_SCSI_MQ_DEFAULT option' (i always set CONFIG_SCSI_MQ_DEFAULT to y, because it sounded interesting). Same problem is also in 3.19 present. Write speeds to a filesystem on that USB-Stick were not so bad, but as i tried to dd in Live-DVD Ubuntu image it was painfully slow. After i disabled CONFIG_SCSI_MQ_DEFAULT write speeds are back to normal. I created bug report in bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=92571 Regards, Andrej -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
