* [PATCH] powerpc: Enable jump label support
@ 2012-05-23 3:58 Anton Blanchard
0 siblings, 0 replies; only message in thread
From: Anton Blanchard @ 2012-05-23 3:58 UTC (permalink / raw)
To: benh, paulus, michael; +Cc: linuxppc-dev
When looking through some instruction traces I noticed our tracepoint
checks were inline. It turns out we don't have CONFIG_JUMP_LABEL
enabled.
By enabling CONFIG_JUMP_LABEL we replace a load/compare/branch with
a nop at every tracepoint call. For example in do_IRQ:
CONFIG_JUMP_LABEL disabled:
stdx 3,11,9
lwz 0,8(29)
cmpwi 7,0,0
bne- 7,.L124
bl .irq_enter
CONFIG_JUMP_LABEL enabled:
stdx 3,11,9
nop
bl .irq_enter
Signed-off-by: Anton Blanchard <anton@samba.org>
---
Index: linux-build/arch/powerpc/configs/ppc64_defconfig
===================================================================
--- linux-build.orig/arch/powerpc/configs/ppc64_defconfig 2012-04-05 13:47:45.691857096 +1000
+++ linux-build/arch/powerpc/configs/ppc64_defconfig 2012-05-23 13:14:04.254270594 +1000
@@ -16,6 +16,7 @@ CONFIG_BLK_DEV_INITRD=y
CONFIG_PROFILING=y
CONFIG_OPROFILE=y
CONFIG_KPROBES=y
+CONFIG_JUMP_LABEL=y
CONFIG_MODULES=y
CONFIG_MODULE_UNLOAD=y
CONFIG_MODVERSIONS=y
Index: linux-build/arch/powerpc/configs/pseries_defconfig
===================================================================
--- linux-build.orig/arch/powerpc/configs/pseries_defconfig 2012-04-05 13:47:45.691857096 +1000
+++ linux-build/arch/powerpc/configs/pseries_defconfig 2012-05-23 13:14:59.783222304 +1000
@@ -24,6 +24,7 @@ CONFIG_BLK_DEV_INITRD=y
CONFIG_PROFILING=y
CONFIG_OPROFILE=y
CONFIG_KPROBES=y
+CONFIG_JUMP_LABEL=y
CONFIG_MODULES=y
CONFIG_MODULE_UNLOAD=y
CONFIG_MODVERSIONS=y
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2012-05-23 3:58 [PATCH] powerpc: Enable jump label support Anton Blanchard
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