correct calculation

Project-OSRM · Apr 20, 2018 · 4e2f6b7 · 4e2f6b7
1 parent e4a4a8d
commit 4e2f6b7
Showing 1 changed file with 39 additions and 15 deletions.
diff --git a/include/engine/unpacking_cache.hpp b/include/engine/unpacking_cache.hpp
@@ -32,28 +32,52 @@ class UnpackingCache
     // https://github.com/Project-OSRM/osrm-backend/issues/4798#issue-288608332)
 
     // LRU CACHE IMPLEMENTATION HAS THESE TWO STORAGE CONTAINERS
-    // Key is of size: std::uint32_t * 2 + (unsigned char) * 1 + unsigned * 1
-    //                = 4 * 2 + 1 * 1 + 4 * 1 =  21
+    // Key is of size: std::uint32_t * 2 + (unsigned char) * 1
+    //                = 4 * 2 + 1 * 1 = 9
     // map: n * Key + n * EdgeDuration
-    //    = n * 21 bytes + n * std::int32_t
-    //    = n * 21 bytes + n * 4 bytes
-    //    = n * 25 bytes
+    //    = n * 9 bytes + n * std::int32_t
+    //    = n * 9 bytes + n * 4 bytes
+    //    = n * 13 bytes
     // list: n * Key
-    //     = n * 21 bytes
-    // Total = n * (25 + 21) = n * 46 bytes
+    //     = n * 9 bytes
+    // Total = n * (13 + 9) = n * 22 bytes
     // Total cache size: 500 mb = 500 * 1024 *1024 bytes = 524288000 bytes
 
-    // THREAD LOCAL STORAGE
-    // Number of lines we need  = 524288000 / 46 / number of threads = 11397565 / number of threads
-    // 16 threads: 11397565 / 16 = 712347
-    // 8 threads: 11397565 / 8 = 1424695
-    // 4 threads: 11397565 / 4 = 2849391
-    // 2 threads: 11397565 / 2 = 5698782
+    // THREAD LOCAL STORAGE (500 mb)
+    // Number of lines we need  = 524288000 / 22 / number of threads = 23831272 / number of threads
+    // 16 threads: 23831272 / 16 = 1489454
+    // 8 threads: 23831272 / 8 = 2978909
+    // 4 threads: 23831272 / 4 = 5957818
+    // 2 threads: 23831272 / 2 = 11915636
+
+    // THREAD LOCAL STORAGE (1024 mb)
+    // Number of lines we need  = 1073741824 / 22 / number of threads = 48806446 / number of threads
+    // 16 threads: 48806446 / 16 = 3050402
+    // 8 threads: 48806446 / 8 = 6100805
+    // 4 threads: 48806446 / 4 = 12201611
+    // 2 threads: 48806446 / 2 = 24403223
+
+    // LRU CACHE IMPLEMENTATION HAS THESE TWO STORAGE CONTAINERS
+    // Key is of size: std::uint32_t * 2 + (unsigned char) * 1 + unsigned * 1
+    //                = 4 * 2 + 1 * 1 + 4 * 1 =  13
+    // map: n * Key + n * EdgeDuration
+    //    = n * 13 bytes + n * std::int32_t
+    //    = n * 13 bytes + n * 4 bytes
+    //    = n * 17 bytes
+    // list: n * Key
+    //     = n * 13 bytes
+    // Total = n * (17 + 13) = n * 30 bytes
+    // Total cache size: 500 mb = 500 * 1024 *1024 bytes = 524288000 bytes
+    // Total cache size: 1024 mb = 1024 * 1024 *1024 bytes = 1073741824 bytes
+    // Total cache size: 250 mb = 250 * 1024 *1024 bytes = 262144000 bytes
 
     // SHARED STORAGE CACHE
-    // Number of lines we need for shared storage cache = 524288000 / 20 = 26214400
+    // Number of lines for shared storage cache 1024 mb = 524288000 / 30 = 17476266
+    // Number of lines for shared storage cache 500 mb = 1073741824 / 30 = 35791394
+    // Number of lines for shared storage cache 250 mb = 262144000 / 30 = 8738133
+
 
-    UnpackingCache(unsigned timestamp) : m_cache(712347), m_current_data_timestamp(timestamp){};
+    UnpackingCache(unsigned timestamp) : m_cache(8738133), m_current_data_timestamp(timestamp){};
 
     UnpackingCache(std::size_t cache_size, unsigned timestamp)
         : m_cache(cache_size), m_current_data_timestamp(timestamp){};