On Wed, 2007-04-18 at 10:21 +0200, Johann Lombardi wrote: > We have observed noticeable performance improvement by using large single > command data transfers (up to 4MB) with some storage subsystems such as DDN's. > The patch below adds a new config option (CONFIG_SCSI_LARGE_SG) which allows to > increase SCSI_MAX_PHYS_SEGMENTS. When enabled, we should get 4MB transfers even > if the buffers are completely fragmented in physical memory. > Thanks in advance for any comments. I don't think so: simply increasing the phys segments has no effect on a fully fragmented sg list if the hw segments doesn't go up to match it. Since changing the hw segments necessitates driver work, I'd really like to see justification in terms of throughput figures versus transfer size rather than vague assertions that bigger is better. James - 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
