>>>>> "Vivek" == Vivek Goyal <vgoyal@xxxxxxxxxx> writes: Vivek> Thinking loud. Will it logically make sense to account for whole Vivek> BIO (all the sectors and not just 1). Target device did the Vivek> actual work of writing the sector. Just that we reduced the data Vivek> transfer overhead. We have absolutely no idea how much work the storage device will do. It could be doing zero-detect or dedup causing it to update an internal allocation map instead of actually writing out blocks. Or it could be forced to do more I/O than we requested due to wear leveling or because it is a RAID device which has to write out full stripes and parity blocks. Vivek> I thought it will make more sense to count WRITE_SAME towards Vivek> number of sectors written and not DISCARDS. Not sure why it make Vivek> sense to count discard sectors towards sectors written in Vivek> disk/part stat. But we're measuring page out activity, right? In my mind the only thing we can reliably measure is the I/O we're transmitting to or receiving from the device. So I'd personally like to see zero for discard and logical block size for write same. -- Martin K. Petersen Oracle Linux Engineering -- 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
