From: Bryan O'Sullivan Date: Sat, 1 Jul 2006 11:36:04 +0000 (-0700) Subject: [PATCH] IB/ipath: reduce overhead on receive interrupts X-Git-Tag: v2.6.18-rc1~225 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=13aef4942c291742064c1d5ac71df6493c4a00a9;p=pandora-kernel.git [PATCH] IB/ipath: reduce overhead on receive interrupts Also count the number of interrupts where that works (fastrcvint). On any interrupt where the port0 head and tail registers are not equal, just call the ipath_kreceive code without reading the interrupt status, thus saving the approximately 0.25usec processor stall waiting for the read to return. If any other interrupt bits are set, or head==tail, take the normal path, but that has been reordered to handle read ahead of pioavail. Also no longer call ipath_kreceive() from ipath_qcheck(), because that just seems to make things worse, and isn't really buying us anything, these days. Also no longer loop in ipath_kreceive(); better to not hold things off too long (I saw many cases where we would loop 4-8 times, and handle thousands (up to 3500) in a single call). Signed-off-by: Dave Olson Signed-off-by: Bryan O'Sullivan Cc: "Michael S. Tsirkin" Cc: Roland Dreier Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed