redis_server_protocol: optimize RedisReply::SerializeTo

src/brpc/redis_command.cpp

@@ -18,29 +18,14 @@
 // Authors: Ge,Jun (gejun@baidu.com)
 
 #include "butil/logging.h"
+#include "butil/string_printf.h"
 #include "brpc/log.h"
 #include "brpc/redis_command.h"
 
-// Defined in src/butil/iobuf.cpp
-void* fast_memcpy(void *__restrict dest, const void *__restrict src, size_t n);
-
 namespace brpc {
 
 const size_t CTX_WIDTH = 5;
 
-// Much faster than snprintf(..., "%lu", d);
-inline size_t AppendDecimal(char* outbuf, unsigned long d) {
-    char buf[24];  // enough for decimal 64-bit integers
-    size_t n = sizeof(buf);
-    do {
-        const unsigned long q = d / 10;
-        buf[--n] = d - q * 10 + '0';
-        d = q;
-    } while (d);
-    fast_memcpy(outbuf, buf + n, sizeof(buf) - n);
-    return sizeof(buf) - n;
-}
-
 // This function is the hotspot of RedisCommandFormatV() when format is
 // short or does not have many %. In a 100K-time call to formating of
 // "GET key1", the time spent on RedisRequest.AddCommand() are ~700ns
@@ -48,7 +33,7 @@ inline size_t AppendDecimal(char* outbuf, unsigned long d) {
 inline void AppendHeader(std::string& buf, char fc, unsigned long value) {
     char header[32];
     header[0] = fc;
-    size_t len = AppendDecimal(header + 1, value);
+    size_t len = butil::AppendDecimal(header + 1, value);
     header[len + 1] = '\r';
     header[len + 2] = '\n';
     buf.append(header, len + 3);
@@ -56,7 +41,7 @@ inline void AppendHeader(std::string& buf, char fc, unsigned long value) {
 inline void AppendHeader(butil::IOBuf& buf, char fc, unsigned long value) {
     char header[32];
     header[0] = fc;
-    size_t len = AppendDecimal(header + 1, value);
+    size_t len = butil::AppendDecimal(header + 1, value);
     header[len + 1] = '\r';
     header[len + 2] = '\n';
     buf.append(header, len + 3);

src/brpc/redis_reply.cpp

@@ -19,6 +19,7 @@
 
 #include <limits>
 #include "butil/logging.h"
+#include "butil/string_printf.h"
 #include "brpc/redis_reply.h"
 
 namespace brpc {
@@ -39,7 +40,8 @@ const char* RedisReplyTypeToString(RedisReplyType type) {
 }
 
 bool RedisReply::SerializeTo(butil::IOBuf* buf) {
-    butil::IOBufBuilder builder;
+    char prefix_buf[24];   // should be enouth for '<type><integer>\r\n"
+    size_t len = 0;
     switch (_type) {
         case REDIS_REPLY_ERROR:
             // fall through
@@ -53,14 +55,20 @@ bool RedisReply::SerializeTo(butil::IOBuf* buf) {
             buf->append("\r\n");
             break;
         case REDIS_REPLY_INTEGER:
-            builder << ':' << _data.integer << "\r\n";
-            buf->append(builder.buf());
+            prefix_buf[0] = ':';
+            len = butil::AppendDecimal(&prefix_buf[1], _data.integer);
+            prefix_buf[len + 1] = '\r';
+            prefix_buf[len + 2] = '\n';
+            buf->append(prefix_buf, len + 3 /* 1 for ':', 2 for "\r\n" */);
             break;
         case REDIS_REPLY_STRING:
-            // Since _length is unsigned, we have to int casting _length to
-            // represent nil string
-            builder << '$' << (int)_length << "\r\n";
-            buf->append(builder.buf());
+            // Since _length is unsigned, we have to casting _length to signed
+            // representing nil string
+            prefix_buf[0] = '$';
+            len = butil::AppendDecimal(&prefix_buf[1], (int)_length);
+            prefix_buf[len + 1] = '\r';
+            prefix_buf[len + 2] = '\n';
+            buf->append(prefix_buf, len + 3 /* 1 for ':', 2 for "\r\n" */);
             if (_length == npos) {
                 break;
             }
@@ -72,8 +80,13 @@ bool RedisReply::SerializeTo(butil::IOBuf* buf) {
             buf->append("\r\n");
             break;
         case REDIS_REPLY_ARRAY:
-            builder << '*' << (int)_length << "\r\n";
-            buf->append(builder.buf());
+            // Since _length is unsigned, we have to casting _length to signed
+            // representing nil string
+            prefix_buf[0] = '*';
+            len = butil::AppendDecimal(&prefix_buf[1], (int)_length);
+            prefix_buf[len + 1] = '\r';
+            prefix_buf[len + 2] = '\n';
+            buf->append(prefix_buf, len + 3 /* 1 for ':', 2 for "\r\n" */);
             if (_length == npos) {
                 break;
             }

src/butil/string_printf.cpp

@@ -137,5 +137,4 @@ int string_vprintf(std::string* output, const char* format, va_list args) {
     return rc;
 };
 
-
 }  // namespace butil

src/butil/string_printf.h

@@ -20,6 +20,7 @@
 
 #include <string>                                // std::string
 #include <stdarg.h>                              // va_list
+#include <string.h>                              // memcpy
 
 namespace butil {
 
@@ -45,6 +46,27 @@ int string_appendf(std::string* output, const char* format, ...)
 // Returns 0 on success, -1 otherwise.
 int string_vappendf(std::string* output, const char* format, va_list args);
 
+// Format integer |d| to |output|, which is much faster than snprintf(..., "%lu", d);
+// Return written length.
+inline size_t AppendDecimal(char* outbuf, long d) {
+    char buf[24];  // enough for decimal 64-bit integers
+    size_t n = sizeof(buf);
+    bool negative = false;
+    if (d < 0) {
+        negative = true;
+        d = -d;
+    }
+    do {
+        const long q = d / 10;
+        buf[--n] = d - q * 10 + '0';
+        d = q;
+    } while (d);
+    if (negative) {
+        buf[--n] = '-';
+    }
+    memcpy(outbuf, buf + n, sizeof(buf) - n);
+    return sizeof(buf) - n;
+}
 
 }  // namespace butil