From: David Daney Date: Thu, 4 Feb 2010 19:31:49 +0000 (-0800) Subject: MIPS: Optimize spinlocks. X-Git-Tag: v2.6.34-rc1~269^2~9 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=500c2e1fdbcc2b273bd4c695a9b8ac8196f61614;p=pandora-kernel.git MIPS: Optimize spinlocks. The current locking mechanism uses a ll/sc sequence to release a spinlock. This is slower than a wmb() followed by a store to unlock. The branching forward to .subsection 2 on sc failure slows down the contended case. So we get rid of that part too. Since we are now working on naturally aligned u16 values, we can get rid of a masking operation as the LHU already does the right thing. The ANDI are reversed for better scheduling on multi-issue CPUs On a 12 CPU 750MHz Octeon cn5750 this patch improves ipv4 UDP packet forwarding rates from 3.58*10^6 PPS to 3.99*10^6 PPS, or about 11%. Signed-off-by: David Daney To: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/937/ Signed-off-by: Ralf Baechle --- Reading git-diff-tree failed