[PATCH for-4.18 4/5] xenalyze: Fix interrupt EIP reporting

[George Dunlap <george.dunlap@xxxxxxxxx>]

EIP lists are generalized across several use cases.  For many of them,
it make sense to have a cycle per sample; but not really for interrupt
EIP lists.  For this reason, it normally just passes 0 as for the tsc
value, which will in turn down at the bottom of update_cycles(),
update only the summary.event_count, but nothing else.

The dump_eip() function attempted to handle this by calling the generic
cycle print handler if the summary contained *any* cycles, and by collecting
and printing its own stats, based solely on counts, if not.

Unfortunately, it used the wrong element for this: it collected the
total from samples.count rather samples.event_count; in the case that
there are no cycles, this will always be zero.  It then divided by
this zero value.  This results in output that looked like this:

```
  ffff89d29656                                             :        0  -nan%
  ffff89d298b6                                             :        0  -nan%
  ffff89d298c0                                             :        0  -nan%
```

It's better than nothing, but a lot less informative than one would
like.

Use event_count rather than count for collecting the total, and the
reporting when there are no cycles in the summary information.  This results
in output that looks like this:

```
   ffff89d29656                                             :        2  1.21%
   ffff89d298b6                                             :        1  0.61%
   ffff89d298c0                                             :        1  0.61%
```

Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxx>
---
Rationale: This is a bug fix.  It's a minor one, but it's also in a
non-critical part of the code.

CC: Anthony Perard <anthony.perard@xxxxxxxxx>
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Xenia Ragiodakou <xenia.ragiadakou@xxxxxxx>
---
 tools/xentrace/xenalyze.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/xentrace/xenalyze.c b/tools/xentrace/xenalyze.c
index 2faf66500d..4b6db59d87 100644
--- a/tools/xentrace/xenalyze.c
+++ b/tools/xentrace/xenalyze.c
@@ -2866,7 +2866,7 @@ void dump_eip(struct eip_list_struct *head) {
 
     for(p=head; p; p=p->next)
     {
-        total += p->summary.count;
+        total += p->summary.event_count;
         N++;
     }
 
@@ -2901,8 +2901,8 @@ void dump_eip(struct eip_list_struct *head) {
                           p->eip,
                           find_symbol(p->eip));
             printf(" %7d %5.2lf%%\n",
-                   p->summary.count,
-                   ((double)p->summary.count*100)/total);
+                   p->summary.event_count,
+                   ((double)p->summary.event_count*100)/total);
         }
 
 
-- 
2.25.1