Avoid the overhead from snprintf

src/zmalloc.c

@@ -737,33 +737,46 @@ size_t zmalloc_get_rss(void) {
 size_t zmalloc_get_frag_smallbins_by_arena(unsigned int arena) {
     unsigned nbins;
     size_t sz, frag = 0;
-    char buf[100];
+
+    /* Pre-convert mallctl paths to MIB for better performance.
+     * This eliminates snprintf and string parsing overhead in the loop. */
+    size_t bin_size_mib[8], bin_nregs_mib[8], curregs_mib[8], curslabs_mib[8];
+    size_t bin_size_miblen = 8, bin_nregs_miblen = 8, curregs_miblen = 8, curslabs_miblen = 8;
 
     sz = sizeof(unsigned);
     assert(!je_mallctl("arenas.nbins", &nbins, &sz, NULL, 0));
+
+    /* Convert all patterns to MIB (required before using je_mallctlbymib) */
+    assert(!je_mallctlnametomib("arenas.bin.0.size", bin_size_mib, &bin_size_miblen));
+    assert(!je_mallctlnametomib("arenas.bin.0.nregs", bin_nregs_mib, &bin_nregs_miblen));
+    assert(!je_mallctlnametomib("stats.arenas.0.bins.0.curregs", curregs_mib, &curregs_miblen));
+    assert(!je_mallctlnametomib("stats.arenas.0.bins.0.curslabs", curslabs_mib, &curslabs_miblen));
+
     for (unsigned j = 0; j < nbins; j++) {
         size_t curregs, curslabs, reg_size;
         uint32_t nregs;
 
         /* The size of the current bin */
-        snprintf(buf, sizeof(buf), "arenas.bin.%u.size", j);
+        bin_size_mib[2] = j;
         sz = sizeof(size_t);
-        assert(!je_mallctl(buf, &reg_size, &sz, NULL, 0));
+        assert(!je_mallctlbymib(bin_size_mib, bin_size_miblen, &reg_size, &sz, NULL, 0));
 
         /* Number of used regions in the bin */
-        snprintf(buf, sizeof(buf), "stats.arenas.%u.bins.%u.curregs", arena, j);
+        curregs_mib[2] = arena;
+        curregs_mib[4] = j;
         sz = sizeof(size_t);
-        assert(!je_mallctl(buf, &curregs, &sz, NULL, 0));
+        assert(!je_mallctlbymib(curregs_mib, curregs_miblen, &curregs, &sz, NULL, 0));
 
         /* Number of regions per slab */
-        snprintf(buf, sizeof(buf), "arenas.bin.%u.nregs", j);
+        bin_nregs_mib[2] = j;
         sz = sizeof(uint32_t);
-        assert(!je_mallctl(buf, &nregs, &sz, NULL, 0));
+        assert(!je_mallctlbymib(bin_nregs_mib, bin_nregs_miblen, &nregs, &sz, NULL, 0));
 
         /* Number of current slabs in the bin */
-        snprintf(buf, sizeof(buf), "stats.arenas.%u.bins.%u.curslabs", arena, j);
+        curslabs_mib[2] = arena;
+        curslabs_mib[4] = j;
         sz = sizeof(size_t);
-        assert(!je_mallctl(buf, &curslabs, &sz, NULL, 0));
+        assert(!je_mallctlbymib(curslabs_mib, curslabs_miblen, &curslabs, &sz, NULL, 0));
 
         /* Calculate the fragmentation bytes for the current bin and add it to the total. */
         frag += ((nregs * curslabs) - curregs) * reg_size;