| commit | 500c2e1fdbcc2b273bd4c695a9b8ac8196f61614 | |
| author | David Daney <ddaney@caviumnetworks.com> | |
| Thu, 4 Feb 2010 19:31:49 +0000 (4 11:31 -0800) | ||
| committer | Ralf Baechle <ralf@linux-mips.org> | |
| Sat, 27 Feb 2010 11:53:42 +0000 (27 12:53 +0100) | ||
| tree | f24c80f609a739beed194fd5c66abf9bc48ce0d6 | treesnapshot (tar.gz zip) |
| parent | e275ed5ee94b358964a0dae1c8b49f0bff260b60 | commitdiff |
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 <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/937/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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 <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/937/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
| arch/mips/include/asm/barrier.h | diffblobblamehistory | |
| arch/mips/include/asm/spinlock.h | diffblobblamehistory | |
| arch/mips/include/asm/spinlock_types.h | diffblobblamehistory |