[PATCH 2/8] dyndbg: motivate a diet plan

[Jim Cromie]

this throwaway patch demonstrates the extra weight:

 dyndbg: 2605 entries. repeated entries: 2369 module 2231 file 1147 func

Thats (91%, 86%, 44%) repeated values in those pointers/columns.

This simple test also shows that a similarly simple run-length encoder
on those 3 columns would compress this table dramatically.

Signed-off-by: Jim Cromie <jim.cro...@gmail.com>
---
 lib/dynamic_debug.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 01b7d0210412..691e79826fc2 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1059,11 +1059,12 @@ static int __init dynamic_debug_init_control(void)
 
 static int __init dynamic_debug_init(void)
 {
-       struct _ddebug *iter, *iter_start;
+       struct _ddebug *iter, *iter_start, *prev = 0;
        const char *modname = NULL;
        char *cmdline;
        int ret = 0;
        int n = 0, entries = 0, modct = 0;
+       int modreps = 0, funcreps = 0, filereps = 0;
 
        if (&__start___dyndbg == &__stop___dyndbg) {
                if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
@@ -1077,7 +1078,16 @@ static int __init dynamic_debug_init(void)
        iter = __start___dyndbg;
        modname = iter->modname;
        iter_start = iter;
-       for (; iter < __stop___dyndbg; iter++) {
+       for (prev = iter; iter < __stop___dyndbg; iter++) {
+               if (entries) {
+                       if (prev->site->modname == iter->site->modname)
+                               modreps++;
+                       if (prev->site->function == iter->site->function)
+                               funcreps++;
+                       if (prev->site->filename == iter->site->filename)
+                               filereps++;
+                       prev++; /* one behind iter */
+               }
                entries++;
                if (strcmp(modname, iter->modname)) {
                        modct++;
@@ -1099,6 +1109,9 @@ static int __init dynamic_debug_init(void)
                 modct, entries, (int)(modct * sizeof(struct ddebug_table)),
                 (int)(entries * sizeof(struct _ddebug)));
 
+       vpr_info("%d entries. repeated entries: %d module %d file %d func\n",
+                entries, modreps, filereps, funcreps);
+
        /* apply ddebug_query boot param, dont unload tables on err */
        if (ddebug_setup_string[0] != '\0') {
                pr_warn("ddebug_query param name is deprecated, change it to 
dyndbg\n");
-- 
2.26.2


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