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| author | Namhyung Kim <namhyung@kernel.org> | 2016-06-29 12:56:48 +0200 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2016-07-05 23:28:30 +0200 |
| commit | a4a551b8f1d4c4ebffd0f49dfef44df3128546f8 (patch) | |
| tree | f59e73d2d4265f88018dea61756793eb15797604 /kernel | |
| parent | tracing: Have HIST_TRIGGERS select TRACING (diff) | |
| download | linux-a4a551b8f1d4c4ebffd0f49dfef44df3128546f8.tar.xz linux-a4a551b8f1d4c4ebffd0f49dfef44df3128546f8.zip | |
ftrace: Reduce size of function graph entries
Currently ftrace_graph_ent{,_entry} and ftrace_graph_ret{,_entry} struct
can have padding bytes at the end due to alignment in 64-bit data type.
As these data are recorded so frequently, those paddings waste
non-negligible space. As the ring buffer maintains alignment properly
for each architecture, just to remove the extra padding using 'packed'
attribute.
ftrace_graph_ent_entry: 24 -> 20
ftrace_graph_ret_entry: 48 -> 44
Also I moved the 'overrun' field in struct ftrace_graph_ret to minimize
the padding in the middle.
Tested on x86_64 only.
Link: http://lkml.kernel.org/r/1467197808-13578-1-git-send-email-namhyung@kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/trace.h | 11 | ||||
| -rw-r--r-- | kernel/trace/trace_entries.h | 4 |
2 files changed, 13 insertions, 2 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index c1de3f493cd3..f783df416726 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -80,6 +80,12 @@ enum trace_type { FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \ filter) +#undef FTRACE_ENTRY_PACKED +#define FTRACE_ENTRY_PACKED(name, struct_name, id, tstruct, print, \ + filter) \ + FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \ + filter) __packed + #include "trace_entries.h" /* @@ -1625,6 +1631,11 @@ int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled); #define FTRACE_ENTRY_DUP(call, struct_name, id, tstruct, print, filter) \ FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print), \ filter) +#undef FTRACE_ENTRY_PACKED +#define FTRACE_ENTRY_PACKED(call, struct_name, id, tstruct, print, filter) \ + FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print), \ + filter) + #include "trace_entries.h" #if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_FUNCTION_TRACER) diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h index ee7b94a4810a..5c30efcda5e6 100644 --- a/kernel/trace/trace_entries.h +++ b/kernel/trace/trace_entries.h @@ -72,7 +72,7 @@ FTRACE_ENTRY_REG(function, ftrace_entry, ); /* Function call entry */ -FTRACE_ENTRY(funcgraph_entry, ftrace_graph_ent_entry, +FTRACE_ENTRY_PACKED(funcgraph_entry, ftrace_graph_ent_entry, TRACE_GRAPH_ENT, @@ -88,7 +88,7 @@ FTRACE_ENTRY(funcgraph_entry, ftrace_graph_ent_entry, ); /* Function return entry */ -FTRACE_ENTRY(funcgraph_exit, ftrace_graph_ret_entry, +FTRACE_ENTRY_PACKED(funcgraph_exit, ftrace_graph_ret_entry, TRACE_GRAPH_RET, |