[perf] move small string map tweaks

Author: tstack

src/base/small_string_map.cc

@@ -32,7 +32,7 @@
 namespace lnav {
 
 std::optional<uint32_t>
-small_string_map::lookup(const string_fragment& in) const
+small_string_map::lookup(const string_fragment& in)
 {
     if (in.length() > MAX_KEY_SIZE) {
         return std::nullopt;
@@ -41,26 +41,16 @@ small_string_map::lookup(const string_fragment& in) const
     alignas(8) char in_key[MAX_KEY_SIZE]{};
     memcpy(in_key, in.data(), in.length());
 
+    auto index = this->ssm_start_index;
     for (int lpc = 0; lpc < MAP_SIZE; ++lpc) {
-        auto match = true;
-#if 0
-        for (int index = 0; index < MAX_KEY_SIZE; ++index) {
-            if (this->ssm_keys[lpc * MAX_KEY_SIZE + index] != in_key[index]) {
-                match = false;
-            }
-        }
-#else
-        if (memcmp(&this->ssm_keys[lpc * MAX_KEY_SIZE], in_key, MAX_KEY_SIZE)
-            != 0)
+        if (memcmp(&this->ssm_keys[index * MAX_KEY_SIZE], in_key, MAX_KEY_SIZE)
+            == 0)
         {
-            match = false;
-        }
-#endif
-        if (match) {
-            return this->ssm_values[lpc];
+            this->ssm_start_index = index;
+            return index;
         }
+        index = (index + 1) % MAP_SIZE;
     }
-
     return std::nullopt;
 }
 

src/base/small_string_map.hh

@@ -43,8 +43,9 @@ struct small_string_map {
     char ssm_keys[MAP_SIZE * MAX_KEY_SIZE]{};
     uint32_t ssm_values[MAP_SIZE]{};
     uint32_t ssm_used_keys{0};
+    uint32_t ssm_start_index{0};
 
-    std::optional<uint32_t> lookup(const string_fragment& in) const;
+    std::optional<uint32_t> lookup(const string_fragment& in);
     void insert(const string_fragment& key, uint32_t value);
 };
 

src/log_format.cc

@@ -4494,33 +4494,12 @@ external_log_format::convert_level(string_fragment sf,
     auto retval = LEVEL_INFO;
 
     if (sf.is_valid()) {
-        // std::optional<uint32_t> ssm_res;
         if (sbc != nullptr) {
             auto ssm_res = sbc->sbc_level_cache.lookup(sf);
             if (ssm_res.has_value()) {
                 return static_cast<log_level_t>(ssm_res.value());
             }
         }
-#if 0
-        if (sbc != nullptr && sbc->sbc_cached_level_count > 0) {
-            const auto level_end = std::begin(sbc->sbc_cached_level_strings)
-                + sbc->sbc_cached_level_count;
-            const auto cached_level_iter = std::find(
-                std::begin(sbc->sbc_cached_level_strings), level_end, sf);
-            if (cached_level_iter != level_end) {
-                const auto cache_index
-                    = std::distance(std::begin(sbc->sbc_cached_level_strings),
-                                    cached_level_iter);
-                if (cache_index != 0) {
-                    std::swap(sbc->sbc_cached_level_strings[cache_index],
-                              sbc->sbc_cached_level_strings[0]);
-                    std::swap(sbc->sbc_cached_level_values[cache_index],
-                              sbc->sbc_cached_level_values[0]);
-                }
-                return sbc->sbc_cached_level_values[0];
-            }
-        }
-#endif
 
         if (this->elf_level_patterns.empty()) {
             retval = string2level(sf.data(), sf.length());
@@ -4537,19 +4516,9 @@ external_log_format::convert_level(string_fragment sf,
             }
         }
 
-        if (sbc != nullptr && sf.length() < 8) {
-#if 0
-            size_t cache_index;
-
-            if (sbc->sbc_cached_level_count == 4) {
-                cache_index = sbc->sbc_cached_level_count - 1;
-            } else {
-                cache_index = sbc->sbc_cached_level_count;
-                sbc->sbc_cached_level_count += 1;
-            }
-            sbc->sbc_cached_level_strings[cache_index] = sf.to_string();
-            sbc->sbc_cached_level_values[cache_index] = retval;
-#endif
+        if (sbc != nullptr
+            && sf.length() <= lnav::small_string_map::MAX_KEY_SIZE)
+        {
             sbc->sbc_level_cache.insert(sf, retval);
         }
     }