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 <an...@samba.org> --- diff --git a/arch/powerpc/kernel/vdso32/vdso32_wrapper.S b/arch/powerpc/kernel/vdso32/vdso32_wrapper.S index 6e8f507..37e2e13 100644 --- a/arch/powerpc/kernel/vdso32/vdso32_wrapper.S +++ b/arch/powerpc/kernel/vdso32/vdso32_wrapper.S @@ -7,7 +7,7 @@ .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 b8553d6..01e7799 100644 --- a/arch/powerpc/kernel/vdso64/vdso64_wrapper.S +++ b/arch/powerpc/kernel/vdso64/vdso64_wrapper.S @@ -7,7 +7,7 @@ .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: _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev