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| author |   Heiko Carstens <heiko.carstens@de.ibm.com> | 2015-01-09 13:08:28 +0100 |
|---|---|---|
| committer |   Martin Schwidefsky <schwidefsky@de.ibm.com> | 2015-01-29 09:19:25 +0100 |
| commit | e6d60b368b45b9be3aa068f8e5fa98c3487c9d4e (patch) | |
| tree | abe83543f72b5cd5d5de309dab8551f93c34f023 /arch/s390/Kconfig | |
| parent | ftrace: let notrace function attribute disable hotpatching if necessary (diff) | |
| download | linux-dev-e6d60b368b45b9be3aa068f8e5fa98c3487c9d4e.tar.xz linux-dev-e6d60b368b45b9be3aa068f8e5fa98c3487c9d4e.zip | |
s390/ftrace: hotpatch support for function tracing
Make use of gcc's hotpatch support to generate better code for ftrace
function tracing.
The generated code now contains only a six byte nop in each function
prologue instead of a 24 byte code block which will be runtime patched to
support function tracing.
With the new code generation the runtime overhead for supporting function
tracing is close to zero, while the original code did show a significant
performance impact.
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/Kconfig')
| -rw-r--r-- | arch/s390/Kconfig | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 7eba5b5723e9..8d11babf9aa5 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -117,7 +117,6 @@ config S390 select HAVE_BPF_JIT if 64BIT && PACK_STACK select HAVE_CMPXCHG_DOUBLE select HAVE_CMPXCHG_LOCAL - select HAVE_C_RECORDMCOUNT select HAVE_DEBUG_KMEMLEAK select HAVE_DYNAMIC_FTRACE if 64BIT select HAVE_DYNAMIC_FTRACE_WITH_REGS if 64BIT |