diff options
author | Anton Blanchard <anton@samba.org> | 2009-10-26 18:50:29 (GMT) |
---|---|---|
committer | Paul Mackerras <paulus@samba.org> | 2009-10-28 05:13:04 (GMT) |
commit | c8cd093a6e9f96ea6b871576fd4e46d7c818bb89 (patch) | |
tree | 2bad2c3a2cc68a35fb93d986a49bf543efcd0156 /arch/powerpc/platforms/pseries/lpar.c | |
parent | 6795b85c6a4f690e61e7be31aa150d945c723fb5 (diff) | |
download | linux-fsl-qoriq-c8cd093a6e9f96ea6b871576fd4e46d7c818bb89.tar.xz |
powerpc: tracing: Add hypervisor call tracepoints
Add hcall_entry and hcall_exit tracepoints. This replaces the inline
assembly HCALL_STATS code and converts it to use the new tracepoints.
To keep the disabled case as quick as possible, we embed a status word
in the TOC so we can get at it with a single load. By doing so we
keep the overhead at a minimum. Time taken for a null hcall:
No tracepoint code: 135.79 cycles
Disabled tracepoints: 137.95 cycles
For reference, before this patch enabling HCALL_STATS resulted in a null
hcall of 201.44 cycles!
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/platforms/pseries/lpar.c')
-rw-r--r-- | arch/powerpc/platforms/pseries/lpar.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c index 903eb9e..4b7b6e8 100644 --- a/arch/powerpc/platforms/pseries/lpar.c +++ b/arch/powerpc/platforms/pseries/lpar.c @@ -39,6 +39,7 @@ #include <asm/cputable.h> #include <asm/udbg.h> #include <asm/smp.h> +#include <asm/trace.h> #include "plpar_wrappers.h" #include "pseries.h" @@ -661,3 +662,34 @@ void arch_free_page(struct page *page, int order) EXPORT_SYMBOL(arch_free_page); #endif + +#ifdef CONFIG_TRACEPOINTS +/* + * We optimise our hcall path by placing hcall_tracepoint_refcount + * directly in the TOC so we can check if the hcall tracepoints are + * enabled via a single load. + */ + +/* NB: reg/unreg are called while guarded with the tracepoints_mutex */ +extern long hcall_tracepoint_refcount; + +void hcall_tracepoint_regfunc(void) +{ + hcall_tracepoint_refcount++; +} + +void hcall_tracepoint_unregfunc(void) +{ + hcall_tracepoint_refcount--; +} + +void __trace_hcall_entry(unsigned long opcode) +{ + trace_hcall_entry(opcode); +} + +void __trace_hcall_exit(long opcode, unsigned long retval) +{ + trace_hcall_exit(opcode, retval); +} +#endif |