Il 07/12/2012 12:20, Kirill A. Shutemov ha scritto: >> > Is this that much faster than scsi-debug? The discarding options surely >> > can be added there. > scsi_ram is about 9% faster (without fake_rw/throw_away_*) on my machine:
There are two main differences in the data path: - scsi_debug uses locking. Shouldn't be the culprit because otherwise read and write would have different speed, but it's easy to add it to scsi_ram and check. - scsi_debug uses scsi_sg_copy_to_buffer, i.e. sg_miter_start/next/stop in kernel/scatterlist.c. Again, it should be easy to port the scsi_ram code to scsi_debug or vice versa and verify if this is the culprit. Having a completely different driver seems useless to me... Paolo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
