Re: 2.5.36-mm1 dbench 512 profiles

[Andrew Morton]

Hanna Linder wrote:
> 
> ...
>         So akpm's removal of lock section directives breaks down the
> functions holding locks that previously were reported under the
> .text.lock.filename?

Yup.  It makes the profiler report the spinlock cost at the
actual callsite.  Patch below.

> Looks like fastwalk might not behave so well
> on this 32 cpu numa system...

I've rather lost the plot.  Have any of the dcache speedup
patches been merged into 2.5?

It would be interesting to know the context switch rate
during this test, and to see what things look like with HZ=100.

--- 2.5.24/include/asm-i386/spinlock.h~spinlock-inline	Fri Jun 21 13:12:01 2002
+++ 2.5.24-akpm/include/asm-i386/spinlock.h	Fri Jun 21 13:18:12 2002
@@ -46,13 +46,13 @@ typedef struct {
 	"\n1:\t" \
 	"lock ; decb %0\n\t" \
 	"js 2f\n" \
-	LOCK_SECTION_START("") \
+	"jmp 3f\n" \
 	"2:\t" \
 	"cmpb $0,%0\n\t" \
 	"rep;nop\n\t" \
 	"jle 2b\n\t" \
 	"jmp 1b\n" \
-	LOCK_SECTION_END
+	"3:\t" \
 
 /*
  * This works. Despite all the confusion.
--- 2.5.24/include/asm-i386/rwlock.h~spinlock-inline	Fri Jun 21 13:18:33 2002
+++ 2.5.24-akpm/include/asm-i386/rwlock.h	Fri Jun 21 13:22:09 2002
@@ -22,25 +22,19 @@
 
 #define __build_read_lock_ptr(rw, helper)   \
 	asm volatile(LOCK "subl $1,(%0)\n\t" \
-		     "js 2f\n" \
-		     "1:\n" \
-		     LOCK_SECTION_START("") \
-		     "2:\tcall " helper "\n\t" \
-		     "jmp 1b\n" \
-		     LOCK_SECTION_END \
+		     "jns 1f\n\t" \
+		     "call " helper "\n\t" \
+		     "1:\t" \
 		     ::"a" (rw) : "memory")
 
 #define __build_read_lock_const(rw, helper)   \
 	asm volatile(LOCK "subl $1,%0\n\t" \
-		     "js 2f\n" \
-		     "1:\n" \
-		     LOCK_SECTION_START("") \
-		     "2:\tpushl %%eax\n\t" \
+		     "jns 1f\n\t" \
+		     "pushl %%eax\n\t" \
 		     "leal %0,%%eax\n\t" \
 		     "call " helper "\n\t" \
 		     "popl %%eax\n\t" \
-		     "jmp 1b\n" \
-		     LOCK_SECTION_END \
+		     "1:\t" \
 		     :"=m" (*(volatile int *)rw) : : "memory")
 
 #define __build_read_lock(rw, helper)	do { \
@@ -52,25 +46,19 @@
 
 #define __build_write_lock_ptr(rw, helper) \
 	asm volatile(LOCK "subl $" RW_LOCK_BIAS_STR ",(%0)\n\t" \
-		     "jnz 2f\n" \
+		     "jz 1f\n\t" \
+		     "call " helper "\n\t" \
 		     "1:\n" \
-		     LOCK_SECTION_START("") \
-		     "2:\tcall " helper "\n\t" \
-		     "jmp 1b\n" \
-		     LOCK_SECTION_END \
 		     ::"a" (rw) : "memory")
 
 #define __build_write_lock_const(rw, helper) \
 	asm volatile(LOCK "subl $" RW_LOCK_BIAS_STR ",%0\n\t" \
-		     "jnz 2f\n" \
-		     "1:\n" \
-		     LOCK_SECTION_START("") \
-		     "2:\tpushl %%eax\n\t" \
+		     "jz 1f\n\t" \
+		     "pushl %%eax\n\t" \
 		     "leal %0,%%eax\n\t" \
 		     "call " helper "\n\t" \
 		     "popl %%eax\n\t" \
-		     "jmp 1b\n" \
-		     LOCK_SECTION_END \
+		     "1:\n" \
 		     :"=m" (*(volatile int *)rw) : : "memory")
 
 #define __build_write_lock(rw, helper)	do { \

-