Messages in this thread | | | From | Nikolay Borisov <> | Subject | Stack trace of csum_partial_copy_generic | Date | Fri, 13 May 2016 14:07:47 +0300 |
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Hello Josh,
I'd like to ask you whether objtool is supposed to produce a warning when arch/x86/lib/csum-copy_64.o (produced from arch/x86/lib/csum-copy_64.S). Since I cannot see any specific usage of rbp for defining a stackframe. I'm chasing against poor performance of a network benchmark and this is what perf produces:
# Overhead Command Shared Object Symbol # ........ ............... ..................... ............................................. # 37.30% iperf [kernel.kallsyms] [k] csum_partial_copy_generic | --- csum_partial_copy_generic | |--99.98%-- 0x7f809108b7cd | | | |--69.72%-- 0x20000 | | | --30.28%-- 0x7f809108b7c2 | 0x20000 --0.02%-- [...]
So this is not very helpful in tracing where this is being called from. Presumably somewhere from the networking layer. So should objtool catch this or since csum_partial_copy_generic is a leaf function reliable stack trace isn't needed? Furthermore this function is called from C wrapper in csum-wrappers_64.c - shouldn't at least they be present in the callstack?
This is on 4.6 master from linus and CONFIG_FRAME_POINTER being enabled.
Regards, Nikolay
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