Provide percentage of memory peak used info.

src/object.c

@@ -810,6 +810,7 @@ struct redisMemOverhead *getMemoryOverheadData(void) {
 
     mh->total_allocated = zmalloc_used;
     mh->startup_allocated = server.initial_memory_usage;
+    mh->peak_allocated = server.stat_peak_memory;
     mem_total += server.initial_memory_usage;
 
     mem = 0;
@@ -889,6 +890,7 @@ struct redisMemOverhead *getMemoryOverheadData(void) {
     if (zmalloc_used > mh->startup_allocated)
         net_usage = zmalloc_used - mh->startup_allocated;
     mh->dataset_perc = (float)mh->dataset*100/net_usage;
+    mh->peak_perc = (float)zmalloc_used*100/mh->peak_allocated;
 
     return mh;
 }
@@ -988,7 +990,10 @@ void memoryCommand(client *c) {
     } else if (!strcasecmp(c->argv[1]->ptr,"overhead") && c->argc == 2) {
         struct redisMemOverhead *mh = getMemoryOverheadData();
 
-        addReplyMultiBulkLen(c,(9+mh->num_dbs)*2);
+        addReplyMultiBulkLen(c,(11+mh->num_dbs)*2);
+
+        addReplyBulkCString(c,"peak.allocated");
+        addReplyLongLong(c,mh->peak_allocated);
 
         addReplyBulkCString(c,"total.allocated");
         addReplyLongLong(c,mh->total_allocated);
@@ -1030,6 +1035,9 @@ void memoryCommand(client *c) {
         addReplyBulkCString(c,"dataset.percentage");
         addReplyDouble(c,mh->dataset_perc);
 
+        addReplyBulkCString(c,"peak.percentage");
+        addReplyDouble(c,mh->peak_perc);
+
         freeMemoryOverheadData(mh);
     } else if (!strcasecmp(c->argv[1]->ptr,"allocator-stats") && c->argc == 2) {
 #if defined(USE_JEMALLOC)

src/server.c

@@ -2837,6 +2837,7 @@ sds genRedisInfoString(char *section) {
             "used_memory_rss_human:%s\r\n"
             "used_memory_peak:%zu\r\n"
             "used_memory_peak_human:%s\r\n"
+            "used_memory_peak_perc:%.2f%%\r\n"
             "used_memory_overhead:%zu\r\n"
             "used_memory_startup:%zu\r\n"
             "used_memory_dataset:%zu\r\n"
@@ -2857,6 +2858,7 @@ sds genRedisInfoString(char *section) {
             used_memory_rss_hmem,
             server.stat_peak_memory,
             peak_hmem,
+            mh->peak_perc,
             mh->overhead_total,
             mh->startup_allocated,
             mh->dataset,

src/server.h

@@ -772,6 +772,7 @@ typedef struct redisOpArray {
 /* This structure is returned by the getMemoryOverheadData() function in
  * order to return memory overhead information. */
 struct redisMemOverhead {
+    size_t peak_allocated;
     size_t total_allocated;
     size_t startup_allocated;
     size_t repl_backlog;
@@ -781,6 +782,7 @@ struct redisMemOverhead {
     size_t overhead_total;
     size_t dataset;
     float dataset_perc;
+    float peak_perc;
     size_t num_dbs;
     struct {
         size_t dbid;