Deprecate WeightedCh4 hash func

Summary: As stated in title - unused.

Reviewed By: lenar-f

Differential Revision: D70400083

fbshipit-source-id: 911d7f28ac2661079bf74206cdc8ab642eaaf07a

Author: Stuart Clark

mcrouter/lib/HashFunctionType.h

@@ -19,6 +19,6 @@ enum class HashFunctionType : uint8_t {
   CRC32 = 3,
   Rendezvous = 4,
   WeightedCh3 = 5,
-  WeightedCh4 = 6,
+  // unused = 6,
   WeightedRendezvous = 7,
 };

mcrouter/lib/Makefile.am

@@ -53,8 +53,6 @@ libmcrouter_a_SOURCES = \
   StatsReply.h \
   WeightedCh3HashFunc.cpp \
   WeightedCh3HashFunc.h \
-  WeightedCh4HashFunc.cpp \
-  WeightedCh4HashFunc.h \
   WeightedChHashFuncBase.cpp \
   WeightedChHashFuncBase.h \
   WeightedRendezvousHashFunc.cpp \

mcrouter/lib/WeightedCh4HashFunc.cpp

@@ -20,7 +20,6 @@ mcrouter_lib_test_SOURCES = \
   RouteHandleTest.cpp \
   WeightedChHashFuncBaseTest.cpp \
   WeightedCh3HashFuncTest.cpp \
-  WeightedCh4HashFuncTest.cpp \
   WeightedRendezvousHashTest.cpp
 
 mcrouter_lib_test_CPPFLAGS = \

mcrouter/lib/WeightedCh4HashFunc.h

@@ -11,13 +11,11 @@
 #include <folly/init/Init.h>
 
 #include "mcrouter/lib/WeightedCh3HashFunc.h"
-#include "mcrouter/lib/WeightedCh4HashFunc.h"
 
 constexpr folly::StringPiece kKey =
     "someKey_ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789+_sdkfjsdfksjdfasdfaksxxx";
 
 using facebook::memcache::WeightedCh3HashFunc;
-using facebook::memcache::WeightedCh4HashFunc;
 
 void weightedCh3Bench(size_t iters, size_t size, double weight, size_t keyLen) {
   std::vector<double> weights;
@@ -32,91 +30,43 @@ void weightedCh3Bench(size_t iters, size_t size, double weight, size_t keyLen) {
   }
 }
 
-void weightedCh4Bench(size_t iters, size_t size, double weight, size_t keyLen) {
-  std::vector<double> weights;
-  BENCHMARK_SUSPEND {
-    weights.resize(size, weight);
-  }
-  folly::StringPiece key =
-      kKey.subpiece(0, keyLen ? keyLen : folly::StringPiece::npos);
-  WeightedCh4HashFunc func(std::move(weights));
-  for (size_t i = 0; i < iters; ++i) {
-    func(key);
-  }
-}
-
 BENCHMARK_NAMED_PARAM(weightedCh3Bench, size_100, 100, 1.0, 0)
-BENCHMARK_RELATIVE_NAMED_PARAM(weightedCh4Bench, size_100, 100, 1.0, 0)
 
 BENCHMARK_NAMED_PARAM(weightedCh3Bench, size_1000, 1000, 1.0, 0)
-BENCHMARK_RELATIVE_NAMED_PARAM(weightedCh4Bench, size_1000, 1000, 1.0, 0)
 
 BENCHMARK_NAMED_PARAM(weightedCh3Bench, size_10000, 10000, 1.0, 0)
-BENCHMARK_RELATIVE_NAMED_PARAM(weightedCh4Bench, size_10000, 10000, 1.0, 0)
 
 BENCHMARK_DRAW_LINE();
 
 BENCHMARK_NAMED_PARAM(weightedCh3Bench, size_100_05, 100, 0.5, 0)
-BENCHMARK_RELATIVE_NAMED_PARAM(weightedCh4Bench, size_100_05, 100, 0.5, 0)
 
 BENCHMARK_NAMED_PARAM(weightedCh3Bench, size_1000_05, 1000, 0.5, 0)
-BENCHMARK_RELATIVE_NAMED_PARAM(weightedCh4Bench, size_1000_05, 1000, 0.5, 0)
 
 BENCHMARK_NAMED_PARAM(weightedCh3Bench, size_10000_05, 10000, 0.5, 0)
-BENCHMARK_RELATIVE_NAMED_PARAM(weightedCh4Bench, size_10000_05, 10000, 0.5, 0)
 
 BENCHMARK_DRAW_LINE();
 
 BENCHMARK_NAMED_PARAM(weightedCh3Bench, size_100_02, 100, 0.2, 0)
-BENCHMARK_RELATIVE_NAMED_PARAM(weightedCh4Bench, size_100_02, 100, 0.2, 0)
 
 BENCHMARK_NAMED_PARAM(weightedCh3Bench, size_1000_02, 1000, 0.2, 0)
-BENCHMARK_RELATIVE_NAMED_PARAM(weightedCh4Bench, size_1000_02, 1000, 0.2, 0)
 
 BENCHMARK_NAMED_PARAM(weightedCh3Bench, size_10000_02, 10000, 0.2, 0)
-BENCHMARK_RELATIVE_NAMED_PARAM(weightedCh4Bench, size_10000_02, 10000, 0.2, 0)
 
 BENCHMARK_DRAW_LINE();
 
 BENCHMARK_NAMED_PARAM(weightedCh3Bench, size_100_short, 100, 1.0, 12)
-BENCHMARK_RELATIVE_NAMED_PARAM(weightedCh4Bench, size_100_short, 100, 1.0, 12)
 
 BENCHMARK_NAMED_PARAM(weightedCh3Bench, size_1000_short, 1000, 1.0, 12)
-BENCHMARK_RELATIVE_NAMED_PARAM(weightedCh4Bench, size_1000_short, 1000, 1.0, 12)
 
 BENCHMARK_NAMED_PARAM(weightedCh3Bench, size_10000_short, 10000, 1.0, 12)
-BENCHMARK_RELATIVE_NAMED_PARAM(
-    weightedCh4Bench,
-    size_10000_short,
-    10000,
-    1.0,
-    12)
 
 BENCHMARK_DRAW_LINE();
 
 BENCHMARK_NAMED_PARAM(weightedCh3Bench, size_100_short_05, 100, 0.5, 12)
-BENCHMARK_RELATIVE_NAMED_PARAM(
-    weightedCh4Bench,
-    size_100_short_05,
-    100,
-    0.5,
-    12)
 
 BENCHMARK_NAMED_PARAM(weightedCh3Bench, size_1000_short_05, 1000, 0.5, 12)
-BENCHMARK_RELATIVE_NAMED_PARAM(
-    weightedCh4Bench,
-    size_1000_short_05,
-    1000,
-    0.5,
-    12)
 
 BENCHMARK_NAMED_PARAM(weightedCh3Bench, size_10000_short_05, 10000, 0.5, 12)
-BENCHMARK_RELATIVE_NAMED_PARAM(
-    weightedCh4Bench,
-    size_10000_short_05,
-    10000,
-    0.5,
-    12)
 
 BENCHMARK_DRAW_LINE();
 

mcrouter/lib/test/Makefile.am

@@ -15,7 +15,6 @@
 #include "mcrouter/lib/RendezvousHashFunc.h"
 #include "mcrouter/lib/SelectionRouteFactory.h"
 #include "mcrouter/lib/WeightedCh3HashFunc.h"
-#include "mcrouter/lib/WeightedCh4HashFunc.h"
 #include "mcrouter/lib/WeightedRendezvousHashFunc.h"
 #include "mcrouter/lib/config/RouteHandleFactory.h"
 #include "mcrouter/lib/routes/NullRoute.h"
@@ -165,10 +164,6 @@ std::shared_ptr<typename RouterInfo::RouteHandleIf> createHashRoute(
         std::move(func),
         bucketize,
         clientFanout);
-  } else if (funcType == WeightedCh4HashFunc::type()) {
-    WeightedCh4HashFunc func{json, n};
-    return createHashRoute<RouterInfo, WeightedCh4HashFunc>(
-        std::move(rh), std::move(salt), std::move(func));
   } else if (funcType == ConstShardHashFunc::type()) {
     return createHashRoute<RouterInfo, ConstShardHashFunc>(
         std::move(rh), std::move(salt), ConstShardHashFunc(n));