Merge pull request #2745 from yahoo/balder/use-thread-local-state

Use a thread local state for faster compression/decompression.

1 files changed, 34 insertions, 3 deletions

diff --git a/document/src/vespa/document/util/zstdcompressor.cpp b/document/src/vespa/document/util/zstdcompressor.cpp
index bb13d8009c1..9bd049fee66 100644
--- a/document/src/vespa/document/util/zstdcompressor.cpp
+++ b/document/src/vespa/document/util/zstdcompressor.cpp
@@ -2,30 +2,61 @@
 
 #include "zstdcompressor.h"
 #include <vespa/vespalib/util/alloc.h>
+#include <vespa/vespalib/util/sync.h>
 #include <zstd.h>
+#include <vector>
 #include <cassert>
 
 using vespalib::alloc::Alloc;
 
 namespace document {
 
+namespace {
+
+class CompressContext {
+public:
+    CompressContext() : _ctx(ZSTD_createCCtx()) {}
+    ~CompressContext() { ZSTD_freeCCtx(_ctx); }
+    ZSTD_CCtx * get() { return _ctx; }
+private:
+    ZSTD_CCtx * _ctx;
+};
+class DecompressContext {
+public:
+    DecompressContext() : _ctx(ZSTD_createDCtx()) {}
+    ~DecompressContext() { ZSTD_freeDCtx(_ctx); }
+    ZSTD_DCtx * get() { return _ctx; }
+private:
+    ZSTD_DCtx * _ctx;
+};
+
+thread_local std::unique_ptr<CompressContext>  _tlCompressState;
+thread_local std::unique_ptr<DecompressContext> _tlDecompressState;
+
+}
+
 size_t ZStdCompressor::adjustProcessLen(uint16_t, size_t len)   const { return ZSTD_compressBound(len); }
 
 bool
 ZStdCompressor::process(const CompressionConfig& config, const void * inputV, size_t inputLen, void * outputV, size_t & outputLenV)
 {
     size_t maxOutputLen = ZSTD_compressBound(inputLen);
-    size_t sz = ZSTD_compress(outputV, maxOutputLen, inputV, inputLen, config.compressionLevel);
+    if ( ! _tlCompressState) {
+        _tlCompressState = std::make_unique<CompressContext>();
+    }
+    size_t sz = ZSTD_compressCCtx(_tlCompressState->get(), outputV, maxOutputLen, inputV, inputLen, config.compressionLevel);
     assert( ! ZSTD_isError(sz) );
     outputLenV = sz;
     return ! ZSTD_isError(sz);
-    
 }
 
 bool
 ZStdCompressor::unprocess(const void * inputV, size_t inputLen, void * outputV, size_t & outputLenV)
 {
-    size_t sz = ZSTD_decompress(outputV, outputLenV, inputV, inputLen);
+    if ( ! _tlDecompressState) {
+        _tlDecompressState = std::make_unique<DecompressContext>();
+    }
+    size_t sz = ZSTD_decompressDCtx(_tlDecompressState->get(), outputV, outputLenV, inputV, inputLen);
     assert( ! ZSTD_isError(sz) );
     outputLenV = sz;
     return ! ZSTD_isError(sz);