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authorAnton Blanchard <anton@au1.ibm.com>2014-02-12 06:18:50 (GMT)
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2014-02-17 00:19:37 (GMT)
commit24b659a13866b935eca72748ce725279bd3c4466 (patch)
tree835ca5a6661974e9e160f921b54cf433f8b1733c /arch/powerpc
parenta0a4419e302fedb548d56129e02130347810f892 (diff)
powerpc: Use unstripped VDSO image for more accurate profiling data
We are seeing a lot of hits in the VDSO that are not resolved by perf. A while(1) gettimeofday() loop shows the issue: 27.64% [vdso] [.] 0x000000000000060c 22.57% [vdso] [.] 0x0000000000000628 16.88% [vdso] [.] 0x0000000000000610 12.39% [vdso] [.] __kernel_gettimeofday 6.09% [vdso] [.] 0x00000000000005f8 3.58% test [.] 00000037.plt_call.gettimeofday@@GLIBC_2.18 2.94% [vdso] [.] __kernel_datapage_offset 2.90% test [.] main We are using a stripped VDSO image which means only symbols with relocation info can be resolved. There isn't a lot of point to stripping the VDSO, the debug info is only about 1kB: 4680 arch/powerpc/kernel/vdso64/vdso64.so 5815 arch/powerpc/kernel/vdso64/vdso64.so.dbg By using the unstripped image, we can resolve all the symbols in the VDSO and the perf profile data looks much better: 76.53% [vdso] [.] __do_get_tspec 12.20% [vdso] [.] __kernel_gettimeofday 5.05% [vdso] [.] __get_datapage 3.20% test [.] main 2.92% test [.] 00000037.plt_call.gettimeofday@@GLIBC_2.18 Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/kernel/vdso32/vdso32_wrapper.S2
-rw-r--r--arch/powerpc/kernel/vdso64/vdso64_wrapper.S2
2 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/vdso32/vdso32_wrapper.S b/arch/powerpc/kernel/vdso32/vdso32_wrapper.S
index 79683d0..6ac107a 100644
--- a/arch/powerpc/kernel/vdso32/vdso32_wrapper.S
+++ b/arch/powerpc/kernel/vdso32/vdso32_wrapper.S
@@ -6,7 +6,7 @@
.globl vdso32_start, vdso32_end
.balign PAGE_SIZE
vdso32_start:
- .incbin "arch/powerpc/kernel/vdso32/vdso32.so"
+ .incbin "arch/powerpc/kernel/vdso32/vdso32.so.dbg"
.balign PAGE_SIZE
vdso32_end:
diff --git a/arch/powerpc/kernel/vdso64/vdso64_wrapper.S b/arch/powerpc/kernel/vdso64/vdso64_wrapper.S
index 8df9e24..df60fca 100644
--- a/arch/powerpc/kernel/vdso64/vdso64_wrapper.S
+++ b/arch/powerpc/kernel/vdso64/vdso64_wrapper.S
@@ -6,7 +6,7 @@
.globl vdso64_start, vdso64_end
.balign PAGE_SIZE
vdso64_start:
- .incbin "arch/powerpc/kernel/vdso64/vdso64.so"
+ .incbin "arch/powerpc/kernel/vdso64/vdso64.so.dbg"
.balign PAGE_SIZE
vdso64_end:

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