tb_flush() calls causing long Windows XP boot times

[Programmingkid]

Hi Richard,

There is a function called breakpoint_invalidate() in cpu.c that calls a 
function called tb_flush(). I have determined that this call is being made over 
200,000 times when Windows XP boots. Disabling this function makes Windows XP 
boot way faster than before. The time went down from around 3 minutes to 20 
seconds when I applied the patch below. 

After I applied the patch I ran several tests in my VM's to see if anything 
broke. I could not find any problems. Here is the list my VM's I tested:

Mac OS 10.8 in qemu-system-x86_64
Windows 7 in qemu-system-x86_64
Windows XP in qemu-system-i386
Mac OS 10.4 in qemu-system-ppc

I would be happy if the patch below was accepted but I would like to know your 
thoughts.

Thank you.


---
 cpu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cpu.c b/cpu.c
index bfbe5a66f9..297c2e4281 100644
--- a/cpu.c
+++ b/cpu.c
@@ -253,7 +253,7 @@ static void breakpoint_invalidate(CPUState *cpu, 
target_ulong pc)
      * Flush the whole TB cache to force re-translation of such TBs.
      * This is heavyweight, but we're debugging anyway.
      */
-    tb_flush(cpu);
+    /* tb_flush(cpu); */
 }
 #endif
 
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