EC-ISA: provide a 10% faster simple parity operation for (k, m=1). Add simple parity...

diff --git a/src/erasure-code/isa/ErasureCodeIsa.cc b/src/erasure-code/isa/ErasureCodeIsa.cc
index 7c997d2c81167c9528b9804d0afd81f8dd806b01..0722374d9a7628aa02fdcf34d1c1bd3aa3b42574 100644 (file)
--- a/src/erasure-code/isa/ErasureCodeIsa.cc
+++ b/src/erasure-code/isa/ErasureCodeIsa.cc
@@ -248,8 +248,13 @@ ErasureCodeIsaDefault::isa_encode(char **data,
                                   char **coding,
                                   int blocksize)
 {
-  ec_encode_data(blocksize, k, m, g_encode_tbls,
-                 (unsigned char**) data, (unsigned char**) coding);
+  
+  if (m==1)
+    // single parity stripe
+    region_xor( (unsigned char**) data, (unsigned char*) coding[0], k, blocksize );
+  else
+    ec_encode_data(blocksize, k, m, g_encode_tbls,
+                  (unsigned char**) data, (unsigned char**) coding);
 }
 
 // -----------------------------------------------------------------------------
@@ -382,6 +387,15 @@ ErasureCodeIsaDefault::isa_decode(int *erasures,
     }
   }
 
+  if (m==1) {
+    // single parity decoding
+    assert (1 == nerrs);
+    dout(20) << "isa_decode: reconstruct using region xor [" << erasures[0] << "]" << dendl;
+    region_xor(recover_source, recover_target[0], k, blocksize);
+    return 0;
+  }
+
+
   if ((matrixtype == kVandermonde) &&
       (nerrs == 1) &&
       (erasures[0] < (k + 1))) {

diff --git a/src/erasure-code/isa/ErasureCodeIsa.h b/src/erasure-code/isa/ErasureCodeIsa.h
index f42756ec67d9a1576451acf9bacfc6eb2cdb04b8..385a8438fa313079064d48b7fe6f9d0b8d8e5a55 100644 (file)
--- a/src/erasure-code/isa/ErasureCodeIsa.h
+++ b/src/erasure-code/isa/ErasureCodeIsa.h
@@ -137,7 +137,7 @@ public:
     return g_decode_tbls_lru.size();
   }
 
-  // we implement an LRU cache for coding matrix - the cache size is sufficient up to (10,4) decodings
+  // we implement an LRU cache for coding matrix - the cache size is sufficient up to (12,4) decodings
   typedef std::pair<std::list<std::string>::iterator, bufferptr> lru_entry_t;
 
   std::map<std::string, lru_entry_t> g_decode_tbls_map;

diff --git a/src/test/erasure-code/TestErasureCodeIsa.cc b/src/test/erasure-code/TestErasureCodeIsa.cc
index d08d05ab8a937aceb6518610e4fe3d57253b1d45..bbef4ab2aed6681a4df571f24029dbc3900537d6 100644 (file)
--- a/src/test/erasure-code/TestErasureCodeIsa.cc
+++ b/src/test/erasure-code/TestErasureCodeIsa.cc
@@ -607,6 +607,104 @@ TYPED_TEST(IsaErasureCodeTest, isa_cauchy_exhaustive)
   EXPECT_EQ(2516, Isa.get_tbls_lru_size());
 }
 
+TYPED_TEST(IsaErasureCodeTest, isa_xor_codec)
+{
+  // Test all possible failure scenarios and reconstruction cases for
+  // a (4,1) RAID-5 like configuration 
+
+  TypeParam Isa;
+  map<std::string, std::string> parameters;
+  parameters["k"] = "4";
+  parameters["m"] = "1";
+  Isa.init(parameters);
+
+  int k = 4;
+  int m = 1;
+
+#define LARGE_ENOUGH 2048
+  bufferptr in_ptr(buffer::create_page_aligned(LARGE_ENOUGH));
+  in_ptr.zero();
+  in_ptr.set_length(0);
+  const char *payload =
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
+  in_ptr.append(payload, strlen(payload));
+  bufferlist in;
+  in.push_front(in_ptr);
+
+  set<int>want_to_encode;
+
+  map<int, bufferlist> encoded;
+  for (int i = 0; i < (k + m); i++) {
+    want_to_encode.insert(i);
+  }
+
+
+  EXPECT_EQ(0, Isa.encode(want_to_encode,
+                          in,
+                          &encoded));
+
+  EXPECT_EQ((unsigned) (k + m), encoded.size());
+
+  unsigned length = encoded[0].length();
+
+  for (int i = 0; i < k; i++) {
+    EXPECT_EQ(0, strncmp(encoded[i].c_str(), in.c_str() + (i * length), length));
+  }
+
+  buffer::ptr enc[k + m];
+  // create buffers with a copy of the original data to be able to compare it after decoding
+  {
+    for (int i = 0; i < (k + m); i++) {
+      buffer::ptr newenc(buffer::create_page_aligned(LARGE_ENOUGH));
+      enc[i] = newenc;
+      enc[i].zero();
+      enc[i].set_length(0);
+      enc[i].append(encoded[i].c_str(), length);
+    }
+  }
+
+  // loop through all possible loss scenarios
+  bool err = true;
+  int cnt_cf = 0;
+
+  for (int l1 = 0; l1 < (k + m); l1++) {
+    map<int, bufferlist> degraded = encoded;
+    set<int> want_to_decode;
+    degraded.erase(l1);
+    want_to_decode.insert(l1);
+    err = DecodeAndVerify(Isa, degraded, want_to_decode, enc, length);
+    EXPECT_EQ(0, err);
+    cnt_cf++;
+    degraded[l1] = encoded[l1];
+    want_to_decode.erase(l1);
+  }
+  EXPECT_EQ(5, cnt_cf);
+}
+
 int main(int argc, char **argv)
 {
   vector<const char*> args;