perf diff: Use perf_session__fprintf_hists just like 'perf record'

That means that almost everything you can do with 'perf report'
can be done with 'perf diff', for instance:

$ perf record -f find / > /dev/null
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.062 MB perf.data (~2699
samples) ] $ perf record -f find / > /dev/null
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.062 MB perf.data (~2687
samples) ] perf diff | head -8
     9.02%     +1.00%     find  libc-2.10.1.so               [.] _IO_vfprintf_internal
     2.91%     -1.00%     find  [kernel]                     [k] __kmalloc
     2.85%     -1.00%     find  [kernel]                     [k] ext4_htree_store_dirent
     1.99%     -1.00%     find  [kernel]                     [k] _atomic_dec_and_lock
     2.44%                find  [kernel]                     [k] half_md4_transform
$

So if you want to zoom into libc:

$ perf diff --dsos libc-2.10.1.so | head -8
    37.34%                find  [.] _IO_vfprintf_internal
    10.34%                find  [.] __GI_memmove
     8.25%     +2.00%     find  [.] _int_malloc
     5.07%     -1.00%     find  [.] __GI_mempcpy
     7.62%     +2.00%     find  [.] _int_free
$

And if there were multiple commands using libc, it is also
possible to aggregate them all by using --sort symbol:

$ perf diff --dsos libc-2.10.1.so --sort symbol | head -8
    37.34%             [.] _IO_vfprintf_internal
    10.34%             [.] __GI_memmove
     8.25%     +2.00%  [.] _int_malloc
     5.07%     -1.00%  [.] __GI_mempcpy
     7.62%     +2.00%  [.] _int_free
$

The displacement column now is off by default, to use it:

perf diff -m --dsos libc-2.10.1.so --sort symbol | head -8
    37.34%                   [.] _IO_vfprintf_internal
    10.34%                   [.] __GI_memmove
     8.25%     +2.00%        [.] _int_malloc
     5.07%     -1.00%    +2  [.] __GI_mempcpy
     7.62%     +2.00%    -1  [.] _int_free
$

Using -t/--field-separator can be used for scripting:

$ perf diff -t, -m --dsos libc-2.10.1.so --sort symbol | head -8
37.34, , ,[.] _IO_vfprintf_internal
10.34, , ,[.] __GI_memmove
8.25,+2.00%, ,[.] _int_malloc
5.07,-1.00%,  +2,[.] __GI_mempcpy
7.62,+2.00%,  -1,[.] _int_free
6.99,+1.00%,  -1,[.] _IO_new_file_xsputn
1.89,-2.00%,  +4,[.] __readdir64
$

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1260978567-550-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 103 insertions, 23 deletions

diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index 6e416a62e0d..ecf853cdc0b 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -454,34 +454,80 @@ static size_t hist_entry_callchain__fprintf(FILE *fp, struct hist_entry *self,
         return ret;
 }
 
-static size_t hist_entry__fprintf(FILE *fp, struct hist_entry *self,
-                                  struct perf_session *session)
+static size_t hist_entry__fprintf(struct hist_entry *self,
+                                  struct perf_session *session,
+                                  struct perf_session *pair_session,
+                                  bool show_displacement,
+                                  long displacement, FILE *fp)
 {
         struct sort_entry *se;
+        u64 count, total;
+        const char *sep = symbol_conf.field_sep;
         size_t ret;
 
         if (symbol_conf.exclude_other && !self->parent)
                 return 0;
 
-        if (session->events_stats.total)
-                ret = percent_color_fprintf(fp,
-                                            symbol_conf.field_sep ? "%.2f" : "   %6.2f%%",
-                                        (self->count * 100.0) / session->events_stats.total);
+        if (pair_session) {
+                count = self->pair ? self->pair->count : 0;
+                total = pair_session->events_stats.total;
+        } else {
+                count = self->count;
+                total = session->events_stats.total;
+        }
+
+        if (total)
+                ret = percent_color_fprintf(fp, sep ? "%.2f" : "   %6.2f%%",
+                                            (count * 100.0) / total);
         else
-                ret = fprintf(fp, symbol_conf.field_sep ? "%lld" : "%12lld ", self->count);
+                ret = fprintf(fp, sep ? "%lld" : "%12lld ", count);
 
         if (symbol_conf.show_nr_samples) {
-                if (symbol_conf.field_sep)
-                        fprintf(fp, "%c%lld", *symbol_conf.field_sep, self->count);
+                if (sep)
+                        fprintf(fp, "%c%lld", *sep, count);
                 else
-                        fprintf(fp, "%11lld", self->count);
+                        fprintf(fp, "%11lld", count);
+        }
+
+        if (pair_session) {
+                char bf[32];
+                double old_percent = 0, new_percent = 0, diff;
+
+                if (total > 0)
+                        old_percent = (count * 100) / total;
+                if (session->events_stats.total > 0)
+                        new_percent = (self->count * 100) / session->events_stats.total;
+
+                diff = old_percent - new_percent;
+
+                if ((u64)diff != 0)
+                        snprintf(bf, sizeof(bf), "%+4.2F%%", diff);
+                else
+                        snprintf(bf, sizeof(bf), " ");
+
+                if (sep)
+                        ret += fprintf(fp, "%c%s", *sep, bf);
+                else
+                        ret += fprintf(fp, "%11.11s", bf);
+
+                if (show_displacement) {
+                        if (displacement)
+                                snprintf(bf, sizeof(bf), "%+4ld", displacement);
+                        else
+                                snprintf(bf, sizeof(bf), " ");
+
+                        if (sep)
+                                fprintf(fp, "%c%s", *sep, bf);
+                        else
+                                fprintf(fp, "%6.6s", bf);
+                }
         }
 
         list_for_each_entry(se, &hist_entry__sort_list, list) {
                 if (se->elide)
                         continue;
 
-                fprintf(fp, "%s", symbol_conf.field_sep ?: "  ");
+                fprintf(fp, "%s", sep ?: "  ");
                 ret += se->print(fp, self, se->width ? *se->width : 0);
         }
 
@@ -504,29 +550,49 @@ static size_t hist_entry__fprintf(FILE *fp, struct hist_entry *self,
         return ret;
 }
 
-size_t perf_session__fprintf_hists(struct perf_session *self, FILE *fp)
+size_t perf_session__fprintf_hists(struct perf_session *self,
+                                   struct perf_session *pair,
+                                   bool show_displacement, FILE *fp)
 {
-        struct hist_entry *pos;
         struct sort_entry *se;
         struct rb_node *nd;
         size_t ret = 0;
+        unsigned long position = 1;
+        long displacement = 0;
         unsigned int width;
+        const char *sep = symbol_conf.field_sep;
         char *col_width = symbol_conf.col_width_list_str;
 
         init_rem_hits();
 
-        fprintf(fp, "# Overhead");
+        fprintf(fp, "# %s", pair ? "Baseline" : "Overhead");
+
         if (symbol_conf.show_nr_samples) {
-                if (symbol_conf.field_sep)
-                        fprintf(fp, "%cSamples", *symbol_conf.field_sep);
+                if (sep)
+                        fprintf(fp, "%cSamples", *sep);
                 else
                         fputs("  Samples  ", fp);
         }
+
+        if (pair) {
+                if (sep)
+                        ret += fprintf(fp, "%cDelta", *sep);
+                else
+                        ret += fprintf(fp, "  Delta    ");
+
+                if (show_displacement) {
+                        if (sep)
+                                ret += fprintf(fp, "%cDisplacement", *sep);
+                        else
+                                ret += fprintf(fp, " Displ");
+                }
+        }
+
         list_for_each_entry(se, &hist_entry__sort_list, list) {
                 if (se->elide)
                         continue;
-                if (symbol_conf.field_sep) {
-                        fprintf(fp, "%c%s", *symbol_conf.field_sep, se->header);
+                if (sep) {
+                        fprintf(fp, "%c%s", *sep, se->header);
                         continue;
                 }
                 width = strlen(se->header);
@@ -545,12 +611,17 @@ size_t perf_session__fprintf_hists(struct perf_session *self, FILE *fp)
         }
         fprintf(fp, "\n");
 
-        if (symbol_conf.field_sep)
+        if (sep)
                 goto print_entries;
 
         fprintf(fp, "# ........");
         if (symbol_conf.show_nr_samples)
                 fprintf(fp, " ..........");
+        if (pair) {
+                fprintf(fp, " ..........");
+                if (show_displacement)
+                        fprintf(fp, " .....");
+        }
         list_for_each_entry(se, &hist_entry__sort_list, list) {
                 unsigned int i;
 
@@ -565,14 +636,23 @@ size_t perf_session__fprintf_hists(struct perf_session *self, FILE *fp)
                 for (i = 0; i < width; i++)
                         fprintf(fp, ".");
         }
-        fprintf(fp, "\n");
 
-        fprintf(fp, "#\n");
+        fprintf(fp, "\n#\n");
 
 print_entries:
         for (nd = rb_first(&self->hists); nd; nd = rb_next(nd)) {
-                pos = rb_entry(nd, struct hist_entry, rb_node);
-                ret += hist_entry__fprintf(fp, pos, self);
+                struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
+
+                if (show_displacement) {
+                        if (h->pair != NULL)
+                                displacement = ((long)h->pair->position -
+                                                (long)position);
+                        else
+                                displacement = 0;
+                        ++position;
+                }
+                ret += hist_entry__fprintf(h, self, pair, show_displacement,
+                                           displacement, fp);
         }
 
         free(rem_sq_bracket);