From: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> Date: Sun, 20 Jul 2008 09:52:25 -0500 > Since we're using it successfully in parisc, I don't want the block code > removed, but I don't see a reason to force other architectures to use > it. > > However, it has two use cases. One is the legacy one of making rather > dumb I/O cards perform better (which is the primary on on parisc), but > there is a current one making huge transfers go through SCSI using using > the sg_table code. That latter is pretty vital to me since I have to > keep the code working, but I don't really have any SCSI cards that can > take advantage of it without virtual merging. As a slight irony, IBM is > trying to persuade me that a ppc would be better than a parisc for big > endian I/O testing ... so I might just be seeing if I can make virtual > merging work on power too. All of this is gibberish, we've been over this a few times already in this thread. For a dumb I/O card, you advertise SG_ALL capabilities, the IOMMU is going to merge things as it would have anyways, and you have code in the driver to advance SG entries after each "dumb I/O". There is zero value to the vmerge code, the real gains are being realized already. -- 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
