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500c2e1fdb
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>
37 lines
592 B
C
37 lines
592 B
C
#ifndef _ASM_SPINLOCK_TYPES_H
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#define _ASM_SPINLOCK_TYPES_H
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#ifndef __LINUX_SPINLOCK_TYPES_H
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# error "please don't include this file directly"
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#endif
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#include <linux/types.h>
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#include <asm/byteorder.h>
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typedef union {
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/*
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* bits 0..15 : serving_now
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* bits 16..31 : ticket
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*/
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u32 lock;
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struct {
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#ifdef __BIG_ENDIAN
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u16 ticket;
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u16 serving_now;
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#else
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u16 serving_now;
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u16 ticket;
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#endif
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} h;
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} arch_spinlock_t;
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#define __ARCH_SPIN_LOCK_UNLOCKED { .lock = 0 }
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typedef struct {
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volatile unsigned int lock;
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} arch_rwlock_t;
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#define __ARCH_RW_LOCK_UNLOCKED { 0 }
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#endif
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