On Sun, 2005-08-28 at 05:42 -0400, Jeff Garzik wrote: > The constant ATA_SHT_USE_CLUSTERING in include/linux/libata.h controls > the use of SCSI layer's use_clustering feature, for a great many libata > drivers. > > The current setup has clustering disabled, which in theory causes the > block layer to do less work, at the expense of a greater number of > scatter/gather table entries used. > > Any opinions WRT turning on clustering for libata?
in 2.4 clustering was expensive due to a large number of checks that were done (basically the number of fragments got recounted a gazilion times). In 2.6 Jens fixed that afaik to make it basically free... at which point it's a win always. Imo clustering on the driver level should announce driver capabilities. If clustering for some arch/kernel makes it slower, that should be decided at a midlayer level and not in each driver; eg the midlayer would chose to ignore the drivers capabilities. So .. my opinion would be that libata should announce the capability (it seems the code/hw can do it). - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
