perf top: Suppress DSO column if only one is present

E.g.

[root@doppio ~]# perf top -U
---------------------------------------------------------------------------
   PerfTop:     482 irqs/sec  kernel:100.0% [1000Hz cycles],  (all, 2 CPUs)
---------------------------------------------------------------------------
DSO: vmlinux
             samples  pcnt function
             _______ _____ _________________________

              471.00 47.9% read_hpet
               57.00  5.8% acpi_os_read_port
               30.00  3.1% hpet_next_event
               30.00  3.1% find_busiest_group
               22.00  2.2% schedule
               18.00  1.8% sched_clock_local
               14.00  1.4% _spin_lock_irqsave
               14.00  1.4% native_read_tsc
               13.00  1.3% trace_hardirqs_off
                9.00  0.9% fget_light
                9.00  0.9% ioread8
                8.00  0.8% do_sys_poll

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: <1258479655-28662-3-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 32 insertions, 11 deletions

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index a368978d5177..6db0e37ee33b 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -438,8 +438,9 @@ static void print_sym_table(void)
         struct sym_entry *syme, *n;
         struct rb_root tmp = RB_ROOT;
         struct rb_node *nd;
-        int sym_width = 0, dso_width;
+        int sym_width = 0, dso_width = 0;
         const int win_width = winsize.ws_col - 1;
+        struct dso *unique_dso = NULL, *first_dso = NULL;
 
         samples = userspace_samples = 0;
 
@@ -509,7 +510,7 @@ static void print_sym_table(void)
                         printf(", %d CPUs)\n", nr_cpus);
         }
 
-        printf("%-*.*s\n\n", win_width, win_width, graph_dotted_line);
+        printf("%-*.*s\n", win_width, win_width, graph_dotted_line);
 
         if (sym_filter_entry) {
                 show_details(sym_filter_entry);
@@ -525,28 +526,47 @@ static void print_sym_table(void)
                     (int)syme->snap_count < count_filter)
                         continue;
 
+                if (first_dso == NULL)
+                        unique_dso = first_dso = syme->map->dso;
+                else if (syme->map->dso != first_dso)
+                        unique_dso = NULL;
+
+                if (syme->map->dso->long_name_len > dso_width)
+                        dso_width = syme->map->dso->long_name_len;
+
                 if (syme->name_len > sym_width)
                         sym_width = syme->name_len;
         }
 
         printed = 0;
 
+        if (unique_dso)
+                printf("DSO: %s\n", unique_dso->long_name);
+        else {
+                int max_dso_width = winsize.ws_col - sym_width - 29;
+                if (dso_width > max_dso_width)
+                        dso_width = max_dso_width;
+                putchar('\n');
+        }
         if (nr_counters == 1)
                 printf("             samples  pcnt");
         else
                 printf("   weight    samples  pcnt");
 
-        dso_width = winsize.ws_col - sym_width - 29;
-
         if (verbose)
                 printf("         RIP       ");
-        printf(" %-*.*s DSO\n", sym_width, sym_width, "function");
+        printf(" %-*.*s", sym_width, sym_width, "function");
+        if (!unique_dso)
+                printf(" DSO");
+        putchar('\n');
         printf("   %s    _______ _____",
                nr_counters == 1 ? "      " : "______");
         if (verbose)
                 printf(" ________________");
-        printf(" %-*.*s %-*.*s\n\n", sym_width, sym_width, graph_line,
-               dso_width, dso_width, graph_line);
+        printf(" %-*.*s", sym_width, sym_width, graph_line);
+        if (!unique_dso)
+                printf(" %-*.*s", dso_width, dso_width, graph_line);
+        puts("\n");
 
         for (nd = rb_first(&tmp); nd; nd = rb_next(nd)) {
                 struct symbol *sym;
@@ -570,10 +590,11 @@ static void print_sym_table(void)
                 if (verbose)
                         printf(" %016llx", sym->start);
                 printf(" %-*.*s", sym_width, sym_width, sym->name);
-                printf(" %-*.*s", dso_width, dso_width,
-                       dso_width >= syme->map->dso->long_name_len ?
-                                        syme->map->dso->long_name :
-                                        syme->map->dso->short_name);
+                if (!unique_dso)
+                        printf(" %-*.*s", dso_width, dso_width,
+                               dso_width >= syme->map->dso->long_name_len ?
+                                                syme->map->dso->long_name :
+                                                syme->map->dso->short_name);
                 printf("\n");
         }
 }