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Commit 4c5fe5db authored by John David Anglin's avatar John David Anglin Committed by Helge Deller
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parisc: Optimze cache flush algorithms 



The attached patch implements three optimizations:

1) Loops in flush_user_dcache_range_asm, flush_kernel_dcache_range_asm,
purge_kernel_dcache_range_asm, flush_user_icache_range_asm, and
flush_kernel_icache_range_asm are unrolled to reduce branch overhead.

2) The static branch prediction for cmpb instructions in pacache.S have
been reviewed and the operand order adjusted where necessary.

3) For flush routines in cache.c, we purge rather flush when we have no
context.  The pdc instruction at level 0 is not required to write back
dirty lines to memory. This provides a performance improvement over the
fdc instruction if the feature is implemented.

Version 2 adds alternative patching.

The patch provides an average improvement of about 2%.

Signed-off-by: default avatarJohn David Anglin <dave.anglin@bell.net>
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
parent 5a23237f

arch/parisc/kernel/cache.c

+27 −6
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ EXPORT_SYMBOL(dcache_stride); 


void flush_dcache_page_asm(unsigned long phys_addr, unsigned long vaddr);

EXPORT_SYMBOL(flush_dcache_page_asm);

void purge_dcache_page_asm(unsigned long phys_addr, unsigned long vaddr);

void flush_icache_page_asm(unsigned long phys_addr, unsigned long vaddr);
@@ -303,6 +304,17 @@ __flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr, 
	preempt_enable();

}



static inline void

__purge_cache_page(struct vm_area_struct *vma, unsigned long vmaddr,

		   unsigned long physaddr)

{

	preempt_disable();

	purge_dcache_page_asm(physaddr, vmaddr);

	if (vma->vm_flags & VM_EXEC)

		flush_icache_page_asm(physaddr, vmaddr);

	preempt_enable();

}



void flush_dcache_page(struct page *page)

{

	struct address_space *mapping = page_mapping_file(page);
@@ -563,9 +575,12 @@ void flush_cache_mm(struct mm_struct *mm) 
			pfn = pte_pfn(*ptep);

			if (!pfn_valid(pfn))

				continue;

			if (unlikely(mm->context))

			if (unlikely(mm->context)) {

				flush_tlb_page(vma, addr);

				__flush_cache_page(vma, addr, PFN_PHYS(pfn));

			} else {

				__purge_cache_page(vma, addr, PFN_PHYS(pfn));

			}

		}

	}

}
@@ -600,9 +615,12 @@ void flush_cache_range(struct vm_area_struct *vma, 
			continue;

		pfn = pte_pfn(*ptep);

		if (pfn_valid(pfn)) {

			if (unlikely(vma->vm_mm->context))

			if (unlikely(vma->vm_mm->context)) {

				flush_tlb_page(vma, addr);

				__flush_cache_page(vma, addr, PFN_PHYS(pfn));

			} else {

				__purge_cache_page(vma, addr, PFN_PHYS(pfn));

			}

		}

	}

}
@@ -611,9 +629,12 @@ void 
flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr, unsigned long pfn)

{

	if (pfn_valid(pfn)) {

		if (likely(vma->vm_mm->context))

		if (likely(vma->vm_mm->context)) {

			flush_tlb_page(vma, vmaddr);

			__flush_cache_page(vma, vmaddr, PFN_PHYS(pfn));

		} else {

			__purge_cache_page(vma, vmaddr, PFN_PHYS(pfn));

		}

	}

}

arch/parisc/kernel/pacache.S

+202 −14
Original line number Diff line number Diff line
@@ -838,7 +838,6 @@ ENTRY_CFI(flush_dcache_page_asm) 
	add		%r28, %r25, %r25

	sub		%r25, r31, %r25





1:	fdc,m		r31(%r28)

	fdc,m		r31(%r28)

	fdc,m		r31(%r28)
@@ -854,7 +853,7 @@ ENTRY_CFI(flush_dcache_page_asm) 
	fdc,m		r31(%r28)

	fdc,m		r31(%r28)

	fdc,m		r31(%r28)

	cmpb,COND(<<)	%r28, %r25,1b

	cmpb,COND(>>)	%r25, %r28, 1b /* predict taken */

	fdc,m		r31(%r28)



89:	ALTERNATIVE(88b, 89b, ALT_COND_NO_DCACHE, INSN_NOP)
@@ -863,6 +862,67 @@ ENTRY_CFI(flush_dcache_page_asm) 
	nop

ENDPROC_CFI(flush_dcache_page_asm)



ENTRY_CFI(purge_dcache_page_asm)

	ldil		L%(TMPALIAS_MAP_START), %r28

#ifdef CONFIG_64BIT

#if (TMPALIAS_MAP_START >= 0x80000000)

	depdi		0, 31,32, %r28		/* clear any sign extension */

#endif

	convert_phys_for_tlb_insert20 %r26	/* convert phys addr to tlb insert format */

	depd		%r25, 63,22, %r28	/* Form aliased virtual address 'to' */

	depdi		0, 63,PAGE_SHIFT, %r28	/* Clear any offset bits */

#else

	extrw,u		%r26, 24,25, %r26	/* convert phys addr to tlb insert format */

	depw		%r25, 31,22, %r28	/* Form aliased virtual address 'to' */

	depwi		0, 31,PAGE_SHIFT, %r28	/* Clear any offset bits */

#endif



	/* Purge any old translation */



#ifdef CONFIG_PA20

	pdtlb,l		%r0(%r28)

#else

	tlb_lock	%r20,%r21,%r22

0:	pdtlb		%r0(%r28)

	tlb_unlock	%r20,%r21,%r22

	ALTERNATIVE(0b, 0b+4, ALT_COND_NO_SMP, INSN_PxTLB)

#endif



88:	ldil		L%dcache_stride, %r1

	ldw		R%dcache_stride(%r1), r31



#ifdef CONFIG_64BIT

	depdi,z		1, 63-PAGE_SHIFT,1, %r25

#else

	depwi,z		1, 31-PAGE_SHIFT,1, %r25

#endif

	add		%r28, %r25, %r25

	sub		%r25, r31, %r25



1:      pdc,m		r31(%r28)

	pdc,m		r31(%r28)

	pdc,m		r31(%r28)

	pdc,m		r31(%r28)

	pdc,m		r31(%r28)

	pdc,m		r31(%r28)

	pdc,m		r31(%r28)

	pdc,m		r31(%r28)

	pdc,m		r31(%r28)

	pdc,m		r31(%r28)

	pdc,m		r31(%r28)

	pdc,m		r31(%r28)

	pdc,m		r31(%r28)

	pdc,m		r31(%r28)

	pdc,m		r31(%r28)

	cmpb,COND(>>)	%r25, %r28, 1b /* predict taken */

	pdc,m		r31(%r28)



89:	ALTERNATIVE(88b, 89b, ALT_COND_NO_DCACHE, INSN_NOP)

	sync

	bv		%r0(%r2)

	nop

ENDPROC_CFI(purge_dcache_page_asm)



ENTRY_CFI(flush_icache_page_asm)

	ldil		L%(TMPALIAS_MAP_START), %r28

#ifdef CONFIG_64BIT
@@ -908,7 +968,6 @@ ENTRY_CFI(flush_icache_page_asm) 
	add		%r28, %r25, %r25

	sub		%r25, %r31, %r25





	/* fic only has the type 26 form on PA1.1, requiring an

	 * explicit space specification, so use %sr4 */

1:      fic,m		%r31(%sr4,%r28)
@@ -926,7 +985,7 @@ ENTRY_CFI(flush_icache_page_asm) 
	fic,m		%r31(%sr4,%r28)

	fic,m		%r31(%sr4,%r28)

	fic,m		%r31(%sr4,%r28)

	cmpb,COND(<<)	%r28, %r25,1b

	cmpb,COND(>>)	%r25, %r28, 1b /* predict taken */

	fic,m		%r31(%sr4,%r28)



89:	ALTERNATIVE(88b, 89b, ALT_COND_NO_ICACHE, INSN_NOP)
@@ -947,7 +1006,6 @@ ENTRY_CFI(flush_kernel_dcache_page_asm) 
	add		%r26, %r25, %r25

	sub		%r25, %r23, %r25





1:      fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)
@@ -963,7 +1021,7 @@ ENTRY_CFI(flush_kernel_dcache_page_asm) 
	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	cmpb,COND(<<)		%r26, %r25,1b

	cmpb,COND(>>)	%r25, %r26, 1b /* predict taken */

	fdc,m		%r23(%r26)



89:	ALTERNATIVE(88b, 89b, ALT_COND_NO_DCACHE, INSN_NOP)
@@ -999,7 +1057,7 @@ ENTRY_CFI(purge_kernel_dcache_page_asm) 
	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	cmpb,COND(<<)		%r26, %r25, 1b

	cmpb,COND(>>)	%r25, %r26, 1b /* predict taken */

	pdc,m		%r23(%r26)



89:	ALTERNATIVE(88b, 89b, ALT_COND_NO_DCACHE, INSN_NOP)
@@ -1014,7 +1072,33 @@ ENTRY_CFI(flush_user_dcache_range_asm) 
	ldo		-1(%r23), %r21

	ANDCM		%r26, %r21, %r26



1:      cmpb,COND(<<),n	%r26, %r25, 1b

#ifdef CONFIG_64BIT

	depd,z		%r23, 59, 60, %r21

#else

	depw,z		%r23, 27, 28, %r21

#endif

	add		%r26, %r21, %r22

	cmpb,COND(>>),n	%r22, %r25, 2f /* predict not taken */

1:	add		%r22, %r21, %r22

	fdc,m		%r23(%sr3, %r26)

	fdc,m		%r23(%sr3, %r26)

	fdc,m		%r23(%sr3, %r26)

	fdc,m		%r23(%sr3, %r26)

	fdc,m		%r23(%sr3, %r26)

	fdc,m		%r23(%sr3, %r26)

	fdc,m		%r23(%sr3, %r26)

	fdc,m		%r23(%sr3, %r26)

	fdc,m		%r23(%sr3, %r26)

	fdc,m		%r23(%sr3, %r26)

	fdc,m		%r23(%sr3, %r26)

	fdc,m		%r23(%sr3, %r26)

	fdc,m		%r23(%sr3, %r26)

	fdc,m		%r23(%sr3, %r26)

	fdc,m		%r23(%sr3, %r26)

	cmpb,COND(<<=)	%r22, %r25, 1b /* predict taken */

	fdc,m		%r23(%sr3, %r26)



2:	cmpb,COND(>>),n	%r25, %r26, 2b

	fdc,m		%r23(%sr3, %r26)



89:	ALTERNATIVE(88b, 89b, ALT_COND_NO_DCACHE, INSN_NOP)
@@ -1029,7 +1113,33 @@ ENTRY_CFI(flush_kernel_dcache_range_asm) 
	ldo		-1(%r23), %r21

	ANDCM		%r26, %r21, %r26



1:      cmpb,COND(<<),n	%r26, %r25,1b

#ifdef CONFIG_64BIT

	depd,z		%r23, 59, 60, %r21

#else

	depw,z		%r23, 27, 28, %r21

#endif

	add		%r26, %r21, %r22

	cmpb,COND(>>),n	%r22, %r25, 2f /* predict not taken */

1:	add		%r22, %r21, %r22

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	fdc,m		%r23(%r26)

	cmpb,COND(<<=)	%r22, %r25, 1b /* predict taken */

	fdc,m		%r23(%r26)



2:	cmpb,COND(>>),n	%r25, %r26, 2b /* predict taken */

	fdc,m		%r23(%r26)



	sync
@@ -1045,7 +1155,33 @@ ENTRY_CFI(purge_kernel_dcache_range_asm) 
	ldo		-1(%r23), %r21

	ANDCM		%r26, %r21, %r26



1:      cmpb,COND(<<),n	%r26, %r25,1b

#ifdef CONFIG_64BIT

	depd,z		%r23, 59, 60, %r21

#else

	depw,z		%r23, 27, 28, %r21

#endif

	add		%r26, %r21, %r22

	cmpb,COND(>>),n	%r22, %r25, 2f /* predict not taken */

1:	add		%r22, %r21, %r22

	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	pdc,m		%r23(%r26)

	cmpb,COND(<<=)	%r22, %r25, 1b /* predict taken */

	pdc,m		%r23(%r26)



2:	cmpb,COND(>>),n	%r25, %r26, 2b /* predict taken */

	pdc,m		%r23(%r26)



	sync
@@ -1061,7 +1197,33 @@ ENTRY_CFI(flush_user_icache_range_asm) 
	ldo		-1(%r23), %r21

	ANDCM		%r26, %r21, %r26



1:      cmpb,COND(<<),n	%r26, %r25,1b

#ifdef CONFIG_64BIT

	depd,z		%r23, 59, 60, %r21

#else

	depw,z		%r23, 27, 28, %r21

#endif

	add		%r26, %r21, %r22

	cmpb,COND(>>),n	%r22, %r25, 2f /* predict not taken */

1:	add		%r22, %r21, %r22

	fic,m		%r23(%sr3, %r26)

	fic,m		%r23(%sr3, %r26)

	fic,m		%r23(%sr3, %r26)

	fic,m		%r23(%sr3, %r26)

	fic,m		%r23(%sr3, %r26)

	fic,m		%r23(%sr3, %r26)

	fic,m		%r23(%sr3, %r26)

	fic,m		%r23(%sr3, %r26)

	fic,m		%r23(%sr3, %r26)

	fic,m		%r23(%sr3, %r26)

	fic,m		%r23(%sr3, %r26)

	fic,m		%r23(%sr3, %r26)

	fic,m		%r23(%sr3, %r26)

	fic,m		%r23(%sr3, %r26)

	fic,m		%r23(%sr3, %r26)

	cmpb,COND(<<=)	%r22, %r25, 1b /* predict taken */

	fic,m		%r23(%sr3, %r26)



2:	cmpb,COND(>>),n	%r25, %r26, 2b

	fic,m		%r23(%sr3, %r26)



89:	ALTERNATIVE(88b, 89b, ALT_COND_NO_ICACHE, INSN_NOP)
@@ -1098,7 +1260,7 @@ ENTRY_CFI(flush_kernel_icache_page) 
	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	cmpb,COND(<<)		%r26, %r25, 1b

	cmpb,COND(>>)	%r25, %r26, 1b /* predict taken */

	fic,m		%r23(%sr4, %r26)



89:	ALTERNATIVE(88b, 89b, ALT_COND_NO_ICACHE, INSN_NOP)
@@ -1113,7 +1275,33 @@ ENTRY_CFI(flush_kernel_icache_range_asm) 
	ldo		-1(%r23), %r21

	ANDCM		%r26, %r21, %r26



1:      cmpb,COND(<<),n	%r26, %r25, 1b

#ifdef CONFIG_64BIT

	depd,z		%r23, 59, 60, %r21

#else

	depw,z		%r23, 27, 28, %r21

#endif

	add		%r26, %r21, %r22

	cmpb,COND(>>),n	%r22, %r25, 2f /* predict not taken */

1:	add		%r22, %r21, %r22

	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	fic,m		%r23(%sr4, %r26)

	cmpb,COND(<<=)	%r22, %r25, 1b /* predict taken */

	fic,m		%r23(%sr4, %r26)



2:	cmpb,COND(>>),n	%r25, %r26, 2b /* predict taken */

	fic,m		%r23(%sr4, %r26)



89:	ALTERNATIVE(88b, 89b, ALT_COND_NO_ICACHE, INSN_NOP)