perf annotate: Cache debuginfo for data type profiling

In find_data_type(), it creates and deletes a debug info whenver it
tries to find data type for a sample.  This is inefficient and it most
likely accesses the same binary again and again.

Let's add a single entry cache the debug info structure for the last DSO.
Depending on sample data, it usually gives me 2~3x (and sometimes more)
speed ups.

Note that this will introduce a little difference in the output due to
the order of checking stack operations.  It used to check the stack ops
before checking the availability of debug info but I moved it after the
symbol check.  So it'll report stack operations in DSOs without debug
info as unknown.  But I think it's ok and better to have the checking
near the caching logic.

Committer testing:

  root@x1:~# perf mem record -a sleep 5s
  root@x1:~# perf evlist
  cpu_atom/mem-loads,ldlat=30/P
  cpu_atom/mem-stores/P
  dummy:u
  root@x1:~# diff -u before after
  --- before	2024-08-08 09:33:53.880780784 -0300
  +++ after	2024-08-08 09:35:13.917325041 -0300
  @@ -81,8 +81,8 @@
   # Overhead  Data Type
   # ........  .........
   #
  -    55.43%  (unknown)
  -    11.61%  (stack operation)
  +    55.56%  (unknown)
  +    11.48%  (stack operation)
        4.93%  struct pcpu_hot
        3.26%  unsigned int
        2.48%  struct

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240805234648.1453689-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c
index 734acdd8c4b71b71bf550e41c260e64566c5d5ee..f125ac5f0bdacb2fab4a29476ee9506f4bebb083 100644 (file)
--- a/tools/perf/util/annotate-data.c
+++ b/tools/perf/util/annotate-data.c
@@ -1345,16 +1345,9 @@ out:
  */
 struct annotated_data_type *find_data_type(struct data_loc_info *dloc)
 {
-       struct annotated_data_type *result = NULL;
        struct dso *dso = map__dso(dloc->ms->map);
        Dwarf_Die type_die;
 
-       dloc->di = debuginfo__new(dso__long_name(dso));
-       if (dloc->di == NULL) {
-               pr_debug_dtp("cannot get the debug info\n");
-               return NULL;
-       }
-
        /*
         * The type offset is the same as instruction offset by default.
         * But when finding a global variable, the offset won't be valid.
@@ -1364,13 +1357,9 @@ struct annotated_data_type *find_data_type(struct data_loc_info *dloc)
        dloc->fbreg = -1;
 
        if (find_data_type_die(dloc, &type_die) < 0)
-               goto out;
-
-       result = dso__findnew_data_type(dso, &type_die);
+               return NULL;
 
-out:
-       debuginfo__delete(dloc->di);
-       return result;
+       return dso__findnew_data_type(dso, &type_die);
 }
 
 static int alloc_data_type_histograms(struct annotated_data_type *adt, int nr_entries)

diff --git a/tools/perf/util/annotate-data.h b/tools/perf/util/annotate-data.h
index 992b7ce4bd11e8f0eeb746e3c27531300f450eb9..37a1a3b68e0b6042d74671f41b4243a127255f9a 100644 (file)
--- a/tools/perf/util/annotate-data.h
+++ b/tools/perf/util/annotate-data.h
@@ -123,9 +123,9 @@ struct data_loc_info {
        u64 var_addr;
        u8 cpumode;
        struct annotated_op_loc *op;
+       struct debuginfo *di;
 
        /* These are used internally */
-       struct debuginfo *di;
        int fbreg;
        bool fb_cfa;
 

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index eafe8d65052e770c9d38e64007929472681fae58..a87d2e97e10d1f016f46c0dfa37dee59993a4904 100644 (file)
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -25,6 +25,7 @@
 #include "srcline.h"
 #include "units.h"
 #include "debug.h"
+#include "debuginfo.h"
 #include "annotate.h"
 #include "annotate-data.h"
 #include "evsel.h"
@@ -2333,6 +2334,20 @@ u64 annotate_calc_pcrel(struct map_symbol *ms, u64 ip, int offset,
        return map__rip_2objdump(ms->map, addr);
 }
 
+static struct debuginfo_cache {
+       struct dso *dso;
+       struct debuginfo *dbg;
+} di_cache;
+
+void debuginfo_cache__delete(void)
+{
+       dso__put(di_cache.dso);
+       di_cache.dso = NULL;
+
+       debuginfo__delete(di_cache.dbg);
+       di_cache.dbg = NULL;
+}
+
 /**
  * hist_entry__get_data_type - find data type for given hist entry
  * @he: hist entry
@@ -2367,6 +2382,27 @@ struct annotated_data_type *hist_entry__get_data_type(struct hist_entry *he)
                return NULL;
        }
 
+       /*
+        * di_cache holds a pair of values, but code below assumes
+        * di_cache.dso can be compared/updated and di_cache.dbg can be
+        * read/updated independently from each other. That assumption only
+        * holds in single threaded code.
+        */
+       assert(perf_singlethreaded);
+
+       if (map__dso(ms->map) != di_cache.dso) {
+               dso__put(di_cache.dso);
+               di_cache.dso = dso__get(map__dso(ms->map));
+
+               debuginfo__delete(di_cache.dbg);
+               di_cache.dbg = debuginfo__new(dso__long_name(di_cache.dso));
+       }
+
+       if (di_cache.dbg == NULL) {
+               ann_data_stat.no_dbginfo++;
+               return NULL;
+       }
+
        /* Make sure it has the disasm of the function */
        if (symbol__annotate(ms, evsel, &arch) < 0) {
                ann_data_stat.no_insn++;
@@ -2411,6 +2447,7 @@ retry:
                        .ip = ms->sym->start + dl->al.offset,
                        .cpumode = he->cpumode,
                        .op = op_loc,
+                       .di = di_cache.dbg,
                };
 
                if (!op_loc->mem_ref && op_loc->segment == INSN_SEG_NONE)

diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
index 64e70d716ff115dace647ec0e564abb27e593815..0e52558baa01f89773da0182bd0d0532bce92454 100644 (file)
--- a/tools/perf/util/annotate.h
+++ b/tools/perf/util/annotate.h
@@ -543,4 +543,6 @@ struct annotated_basic_block {
 int annotate_get_basic_blocks(struct symbol *sym, s64 src, s64 dst,
                              struct list_head *head);
 
+void debuginfo_cache__delete(void);
+
 #endif /* __PERF_ANNOTATE_H */

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 5596bed1b8c83f3a8b295c97fba9592ff01f09f5..f9072e003367f4251e28b8009c0677f71158192d 100644 (file)
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -36,6 +36,7 @@
 #include "util.h"
 #include "arch/common.h"
 #include "units.h"
+#include "annotate.h"
 #include <internal/lib.h>
 
 #ifdef HAVE_ZSTD_SUPPORT
@@ -304,6 +305,7 @@ void perf_session__delete(struct perf_session *session)
                return;
        auxtrace__free(session);
        auxtrace_index__free(&session->auxtrace_index);
+       debuginfo_cache__delete();
        perf_session__destroy_kernel_maps(session);
        perf_decomp__release_events(session->decomp_data.decomp);
        perf_env__exit(&session->header.env);