Improve multithreaded performance with memory prefetching (#861)

This PR utilizes the IO threads to execute commands in batches, allowing
us to prefetch the dictionary data in advance.

After making the IO threads asynchronous and offloading more work to
them in the first 2 PRs, the `lookupKey` function becomes a main
bottle-neck and it takes about 50% of the main-thread time (Tested with
SET command). This is because the Valkey dictionary is a straightforward
but inefficient chained hash implementation. While traversing the hash
linked lists, every access to either a dictEntry structure, pointer to
key, or a value object requires, with high probability, an expensive
external memory access.

### Memory Access Amortization

Memory Access Amortization (MAA) is a technique designed to optimize the
performance of dynamic data structures by reducing the impact of memory
access latency. It is applicable when multiple operations need to be
executed concurrently. The principle behind it is that for certain
dynamic data structures, executing operations in a batch is more
efficient than executing each one separately.

Rather than executing operations sequentially, this approach interleaves
the execution of all operations. This is done in such a way that
whenever a memory access is required during an operation, the program
prefetches the necessary memory and transitions to another operation.
This ensures that when one operation is blocked awaiting memory access,
other memory accesses are executed in parallel, thereby reducing the
average access latency.

We applied this method in the development of `dictPrefetch`, which takes
as parameters a vector of keys and dictionaries. It ensures that all
memory addresses required to execute dictionary operations for these
keys are loaded into the L1-L3 caches when executing commands.
Essentially, `dictPrefetch` is an interleaved execution of dictFind for
all the keys.


**Implementation details**

When the main thread iterates over the `clients-pending-io-read`, for
clients with ready-to-execute commands (i.e., clients for which the IO
thread has parsed the commands), a batch of up to 16 commands is
created. Initially, the command's argv, which were allocated by the IO
thread, is prefetched to the main thread's L1 cache. Subsequently, all
the dict entries and values required for the commands are prefetched
from the dictionary before the command execution. Only then will the
commands be executed.

---------

Signed-off-by: Uri Yagelnik <uriy@amazon.com>

src/Makefile

@@ -423,7 +423,7 @@ endif
 ENGINE_NAME=valkey
 SERVER_NAME=$(ENGINE_NAME)-server$(PROG_SUFFIX)
 ENGINE_SENTINEL_NAME=$(ENGINE_NAME)-sentinel$(PROG_SUFFIX)
-ENGINE_SERVER_OBJ=threads_mngr.o adlist.o quicklist.o ae.o anet.o dict.o kvstore.o server.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o io_threads.o networking.o util.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o cluster_legacy.o cluster_slot_stats.o crc16.o endianconv.o slowlog.o eval.o bio.o rio.o rand.o memtest.o syscheck.o crcspeed.o crccombine.o crc64.o bitops.o sentinel.o notify.o setproctitle.o blocked.o hyperloglog.o latency.o sparkline.o valkey-check-rdb.o valkey-check-aof.o geo.o lazyfree.o module.o evict.o expire.o geohash.o geohash_helper.o childinfo.o defrag.o siphash.o rax.o t_stream.o listpack.o localtime.o lolwut.o lolwut5.o lolwut6.o acl.o tracking.o socket.o tls.o sha256.o timeout.o setcpuaffinity.o monotonic.o mt19937-64.o resp_parser.o call_reply.o script_lua.o script.o functions.o function_lua.o commands.o strl.o connection.o unix.o logreqres.o
+ENGINE_SERVER_OBJ=threads_mngr.o adlist.o quicklist.o ae.o anet.o dict.o kvstore.o server.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o memory_prefetch.o io_threads.o networking.o util.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o cluster_legacy.o cluster_slot_stats.o crc16.o endianconv.o slowlog.o eval.o bio.o rio.o rand.o memtest.o syscheck.o crcspeed.o crccombine.o crc64.o bitops.o sentinel.o notify.o setproctitle.o blocked.o hyperloglog.o latency.o sparkline.o valkey-check-rdb.o valkey-check-aof.o geo.o lazyfree.o module.o evict.o expire.o geohash.o geohash_helper.o childinfo.o defrag.o siphash.o rax.o t_stream.o listpack.o localtime.o lolwut.o lolwut5.o lolwut6.o acl.o tracking.o socket.o tls.o sha256.o timeout.o setcpuaffinity.o monotonic.o mt19937-64.o resp_parser.o call_reply.o script_lua.o script.o functions.o function_lua.o commands.o strl.o connection.o unix.o logreqres.o
 ENGINE_CLI_NAME=$(ENGINE_NAME)-cli$(PROG_SUFFIX)
 ENGINE_CLI_OBJ=anet.o adlist.o dict.o valkey-cli.o zmalloc.o release.o ae.o serverassert.o crcspeed.o crccombine.o crc64.o siphash.o crc16.o monotonic.o cli_common.o mt19937-64.o strl.o cli_commands.o
 ENGINE_BENCHMARK_NAME=$(ENGINE_NAME)-benchmark$(PROG_SUFFIX)

src/config.c

@@ -3166,6 +3166,7 @@ standardConfig static_configs[] = {
     createIntConfig("port", NULL, MODIFIABLE_CONFIG, 0, 65535, server.port, 6379, INTEGER_CONFIG, NULL, updatePort), /* TCP port. */
     createIntConfig("io-threads", NULL, DEBUG_CONFIG | IMMUTABLE_CONFIG, 1, 128, server.io_threads_num, 1, INTEGER_CONFIG, NULL, NULL), /* Single threaded by default */
     createIntConfig("events-per-io-thread", NULL, MODIFIABLE_CONFIG, 0, INT_MAX, server.events_per_io_thread, 2, INTEGER_CONFIG, NULL, NULL),
+    createIntConfig("prefetch-batch-max-size", NULL, MODIFIABLE_CONFIG, 0, 128, server.prefetch_batch_max_size, 16, INTEGER_CONFIG, NULL, NULL),
     createIntConfig("auto-aof-rewrite-percentage", NULL, MODIFIABLE_CONFIG, 0, INT_MAX, server.aof_rewrite_perc, 100, INTEGER_CONFIG, NULL, NULL),
     createIntConfig("cluster-replica-validity-factor", "cluster-slave-validity-factor", MODIFIABLE_CONFIG, 0, INT_MAX, server.cluster_replica_validity_factor, 10, INTEGER_CONFIG, NULL, NULL), /* replica max data age factor. */
     createIntConfig("list-max-listpack-size", "list-max-ziplist-size", MODIFIABLE_CONFIG, INT_MIN, INT_MAX, server.list_max_listpack_size, -2, INTEGER_CONFIG, NULL, NULL),

src/config.h

@@ -348,4 +348,20 @@ void setcpuaffinity(const char *cpulist);
 #endif
 #endif
 
+/* Check for GCC version >= 4.9 */
+#if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 9))
+#define HAS_BUILTIN_PREFETCH 1
+/* Check for Clang version >= 3.6 */
+#elif defined(__clang__) && (__clang_major__ > 3 || (__clang_major__ == 3 && __clang_minor__ >= 6))
+#define HAS_BUILTIN_PREFETCH 1
+#else
+#define HAS_BUILTIN_PREFETCH 0
+#endif
+
+#if HAS_BUILTIN_PREFETCH
+#define valkey_prefetch(addr) __builtin_prefetch(addr)
+#else
+#define valkey_prefetch(addr) ((void)(addr))
+#endif
+
 #endif

src/dict.c

@@ -48,6 +48,7 @@
 #include "zmalloc.h"
 #include "serverassert.h"
 #include "monotonic.h"
+#include "config.h"
 
 #ifndef static_assert
 #define static_assert(expr, lit) _Static_assert(expr, lit)
@@ -119,7 +120,6 @@ static void _dictExpandIfNeeded(dict *d);
 static void _dictShrinkIfNeeded(dict *d);
 static signed char _dictNextExp(unsigned long size);
 static int _dictInit(dict *d, dictType *type);
-static dictEntry *dictGetNext(const dictEntry *de);
 static dictEntry **dictGetNextRef(dictEntry *de);
 static void dictSetNext(dictEntry *de, dictEntry *next);
 
@@ -962,7 +962,7 @@ double *dictGetDoubleValPtr(dictEntry *de) {
 
 /* Returns the 'next' field of the entry or NULL if the entry doesn't have a
  * 'next' field. */
-static dictEntry *dictGetNext(const dictEntry *de) {
+dictEntry *dictGetNext(const dictEntry *de) {
     if (entryIsKey(de)) return NULL; /* there's no next */
     if (entryIsNoValue(de)) return decodeEntryNoValue(de)->next;
     if (entryIsEmbedded(de)) return decodeEmbeddedEntry(de)->next;

src/dict.h

@@ -229,6 +229,7 @@ void dictInitIterator(dictIterator *iter, dict *d);
 void dictInitSafeIterator(dictIterator *iter, dict *d);
 void dictResetIterator(dictIterator *iter);
 dictEntry *dictNext(dictIterator *iter);
+dictEntry *dictGetNext(const dictEntry *de);
 void dictReleaseIterator(dictIterator *iter);
 dictEntry *dictGetRandomKey(dict *d);
 dictEntry *dictGetFairRandomKey(dict *d);

src/fmtargs.h

@@ -44,9 +44,9 @@
 /* Everything below this line is automatically generated by
  * generate-fmtargs.py. Do not manually edit. */
 
-#define ARG_N(_1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, _25, _26, _27, _28, _29, _30, _31, _32, _33, _34, _35, _36, _37, _38, _39, _40, _41, _42, _43, _44, _45, _46, _47, _48, _49, _50, _51, _52, _53, _54, _55, _56, _57, _58, _59, _60, _61, _62, _63, _64, _65, _66, _67, _68, _69, _70, _71, _72, _73, _74, _75, _76, _77, _78, _79, _80, _81, _82, _83, _84, _85, _86, _87, _88, _89, _90, _91, _92, _93, _94, _95, _96, _97, _98, _99, _100, _101, _102, _103, _104, _105, _106, _107, _108, _109, _110, _111, _112, _113, _114, _115, _116, _117, _118, _119, _120, N, ...) N
+#define ARG_N(_1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, _25, _26, _27, _28, _29, _30, _31, _32, _33, _34, _35, _36, _37, _38, _39, _40, _41, _42, _43, _44, _45, _46, _47, _48, _49, _50, _51, _52, _53, _54, _55, _56, _57, _58, _59, _60, _61, _62, _63, _64, _65, _66, _67, _68, _69, _70, _71, _72, _73, _74, _75, _76, _77, _78, _79, _80, _81, _82, _83, _84, _85, _86, _87, _88, _89, _90, _91, _92, _93, _94, _95, _96, _97, _98, _99, _100, _101, _102, _103, _104, _105, _106, _107, _108, _109, _110, _111, _112, _113, _114, _115, _116, _117, _118, _119, _120, _121, _122, _123, _124, _125, _126, _127, _128, _129, _130, _131, _132, _133, _134, _135, _136, _137, _138, _139, _140, _141, _142, _143, _144, _145, _146, _147, _148, _149, _150, _151, _152, _153, _154, _155, _156, _157, _158, _159, _160, _161, _162, _163, _164, _165, _166, _167, _168, _169, _170, _171, _172, _173, _174, _175, _176, _177, _178, _179, _180, _181, _182, _183, _184, _185, _186, _187, _188, _189, _190, _191, _192, _193, _194, _195, _196, _197, _198, _199, _200, N, ...) N
 
-#define RSEQ_N() 120, 119, 118, 117, 116, 115, 114, 113, 112, 111, 110, 109, 108, 107, 106, 105, 104, 103, 102, 101, 100, 99, 98, 97, 96, 95, 94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0
+#define RSEQ_N() 200, 199, 198, 197, 196, 195, 194, 193, 192, 191, 190, 189, 188, 187, 186, 185, 184, 183, 182, 181, 180, 179, 178, 177, 176, 175, 174, 173, 172, 171, 170, 169, 168, 167, 166, 165, 164, 163, 162, 161, 160, 159, 158, 157, 156, 155, 154, 153, 152, 151, 150, 149, 148, 147, 146, 145, 144, 143, 142, 141, 140, 139, 138, 137, 136, 135, 134, 133, 132, 131, 130, 129, 128, 127, 126, 125, 124, 123, 122, 121, 120, 119, 118, 117, 116, 115, 114, 113, 112, 111, 110, 109, 108, 107, 106, 105, 104, 103, 102, 101, 100, 99, 98, 97, 96, 95, 94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0
 
 #define COMPACT_FMT_2(fmt, value) fmt
 #define COMPACT_FMT_4(fmt, value, ...) fmt COMPACT_FMT_2(__VA_ARGS__)
@@ -108,6 +108,46 @@
 #define COMPACT_FMT_116(fmt, value, ...) fmt COMPACT_FMT_114(__VA_ARGS__)
 #define COMPACT_FMT_118(fmt, value, ...) fmt COMPACT_FMT_116(__VA_ARGS__)
 #define COMPACT_FMT_120(fmt, value, ...) fmt COMPACT_FMT_118(__VA_ARGS__)
+#define COMPACT_FMT_122(fmt, value, ...) fmt COMPACT_FMT_120(__VA_ARGS__)
+#define COMPACT_FMT_124(fmt, value, ...) fmt COMPACT_FMT_122(__VA_ARGS__)
+#define COMPACT_FMT_126(fmt, value, ...) fmt COMPACT_FMT_124(__VA_ARGS__)
+#define COMPACT_FMT_128(fmt, value, ...) fmt COMPACT_FMT_126(__VA_ARGS__)
+#define COMPACT_FMT_130(fmt, value, ...) fmt COMPACT_FMT_128(__VA_ARGS__)
+#define COMPACT_FMT_132(fmt, value, ...) fmt COMPACT_FMT_130(__VA_ARGS__)
+#define COMPACT_FMT_134(fmt, value, ...) fmt COMPACT_FMT_132(__VA_ARGS__)
+#define COMPACT_FMT_136(fmt, value, ...) fmt COMPACT_FMT_134(__VA_ARGS__)
+#define COMPACT_FMT_138(fmt, value, ...) fmt COMPACT_FMT_136(__VA_ARGS__)
+#define COMPACT_FMT_140(fmt, value, ...) fmt COMPACT_FMT_138(__VA_ARGS__)
+#define COMPACT_FMT_142(fmt, value, ...) fmt COMPACT_FMT_140(__VA_ARGS__)
+#define COMPACT_FMT_144(fmt, value, ...) fmt COMPACT_FMT_142(__VA_ARGS__)
+#define COMPACT_FMT_146(fmt, value, ...) fmt COMPACT_FMT_144(__VA_ARGS__)
+#define COMPACT_FMT_148(fmt, value, ...) fmt COMPACT_FMT_146(__VA_ARGS__)
+#define COMPACT_FMT_150(fmt, value, ...) fmt COMPACT_FMT_148(__VA_ARGS__)
+#define COMPACT_FMT_152(fmt, value, ...) fmt COMPACT_FMT_150(__VA_ARGS__)
+#define COMPACT_FMT_154(fmt, value, ...) fmt COMPACT_FMT_152(__VA_ARGS__)
+#define COMPACT_FMT_156(fmt, value, ...) fmt COMPACT_FMT_154(__VA_ARGS__)
+#define COMPACT_FMT_158(fmt, value, ...) fmt COMPACT_FMT_156(__VA_ARGS__)
+#define COMPACT_FMT_160(fmt, value, ...) fmt COMPACT_FMT_158(__VA_ARGS__)
+#define COMPACT_FMT_162(fmt, value, ...) fmt COMPACT_FMT_160(__VA_ARGS__)
+#define COMPACT_FMT_164(fmt, value, ...) fmt COMPACT_FMT_162(__VA_ARGS__)
+#define COMPACT_FMT_166(fmt, value, ...) fmt COMPACT_FMT_164(__VA_ARGS__)
+#define COMPACT_FMT_168(fmt, value, ...) fmt COMPACT_FMT_166(__VA_ARGS__)
+#define COMPACT_FMT_170(fmt, value, ...) fmt COMPACT_FMT_168(__VA_ARGS__)
+#define COMPACT_FMT_172(fmt, value, ...) fmt COMPACT_FMT_170(__VA_ARGS__)
+#define COMPACT_FMT_174(fmt, value, ...) fmt COMPACT_FMT_172(__VA_ARGS__)
+#define COMPACT_FMT_176(fmt, value, ...) fmt COMPACT_FMT_174(__VA_ARGS__)
+#define COMPACT_FMT_178(fmt, value, ...) fmt COMPACT_FMT_176(__VA_ARGS__)
+#define COMPACT_FMT_180(fmt, value, ...) fmt COMPACT_FMT_178(__VA_ARGS__)
+#define COMPACT_FMT_182(fmt, value, ...) fmt COMPACT_FMT_180(__VA_ARGS__)
+#define COMPACT_FMT_184(fmt, value, ...) fmt COMPACT_FMT_182(__VA_ARGS__)
+#define COMPACT_FMT_186(fmt, value, ...) fmt COMPACT_FMT_184(__VA_ARGS__)
+#define COMPACT_FMT_188(fmt, value, ...) fmt COMPACT_FMT_186(__VA_ARGS__)
+#define COMPACT_FMT_190(fmt, value, ...) fmt COMPACT_FMT_188(__VA_ARGS__)
+#define COMPACT_FMT_192(fmt, value, ...) fmt COMPACT_FMT_190(__VA_ARGS__)
+#define COMPACT_FMT_194(fmt, value, ...) fmt COMPACT_FMT_192(__VA_ARGS__)
+#define COMPACT_FMT_196(fmt, value, ...) fmt COMPACT_FMT_194(__VA_ARGS__)
+#define COMPACT_FMT_198(fmt, value, ...) fmt COMPACT_FMT_196(__VA_ARGS__)
+#define COMPACT_FMT_200(fmt, value, ...) fmt COMPACT_FMT_198(__VA_ARGS__)
 
 #define COMPACT_VALUES_2(fmt, value) value
 #define COMPACT_VALUES_4(fmt, value, ...) value, COMPACT_VALUES_2(__VA_ARGS__)
@@ -169,5 +209,45 @@
 #define COMPACT_VALUES_116(fmt, value, ...) value, COMPACT_VALUES_114(__VA_ARGS__)
 #define COMPACT_VALUES_118(fmt, value, ...) value, COMPACT_VALUES_116(__VA_ARGS__)
 #define COMPACT_VALUES_120(fmt, value, ...) value, COMPACT_VALUES_118(__VA_ARGS__)
+#define COMPACT_VALUES_122(fmt, value, ...) value, COMPACT_VALUES_120(__VA_ARGS__)
+#define COMPACT_VALUES_124(fmt, value, ...) value, COMPACT_VALUES_122(__VA_ARGS__)
+#define COMPACT_VALUES_126(fmt, value, ...) value, COMPACT_VALUES_124(__VA_ARGS__)
+#define COMPACT_VALUES_128(fmt, value, ...) value, COMPACT_VALUES_126(__VA_ARGS__)
+#define COMPACT_VALUES_130(fmt, value, ...) value, COMPACT_VALUES_128(__VA_ARGS__)
+#define COMPACT_VALUES_132(fmt, value, ...) value, COMPACT_VALUES_130(__VA_ARGS__)
+#define COMPACT_VALUES_134(fmt, value, ...) value, COMPACT_VALUES_132(__VA_ARGS__)
+#define COMPACT_VALUES_136(fmt, value, ...) value, COMPACT_VALUES_134(__VA_ARGS__)
+#define COMPACT_VALUES_138(fmt, value, ...) value, COMPACT_VALUES_136(__VA_ARGS__)
+#define COMPACT_VALUES_140(fmt, value, ...) value, COMPACT_VALUES_138(__VA_ARGS__)
+#define COMPACT_VALUES_142(fmt, value, ...) value, COMPACT_VALUES_140(__VA_ARGS__)
+#define COMPACT_VALUES_144(fmt, value, ...) value, COMPACT_VALUES_142(__VA_ARGS__)
+#define COMPACT_VALUES_146(fmt, value, ...) value, COMPACT_VALUES_144(__VA_ARGS__)
+#define COMPACT_VALUES_148(fmt, value, ...) value, COMPACT_VALUES_146(__VA_ARGS__)
+#define COMPACT_VALUES_150(fmt, value, ...) value, COMPACT_VALUES_148(__VA_ARGS__)
+#define COMPACT_VALUES_152(fmt, value, ...) value, COMPACT_VALUES_150(__VA_ARGS__)
+#define COMPACT_VALUES_154(fmt, value, ...) value, COMPACT_VALUES_152(__VA_ARGS__)
+#define COMPACT_VALUES_156(fmt, value, ...) value, COMPACT_VALUES_154(__VA_ARGS__)
+#define COMPACT_VALUES_158(fmt, value, ...) value, COMPACT_VALUES_156(__VA_ARGS__)
+#define COMPACT_VALUES_160(fmt, value, ...) value, COMPACT_VALUES_158(__VA_ARGS__)
+#define COMPACT_VALUES_162(fmt, value, ...) value, COMPACT_VALUES_160(__VA_ARGS__)
+#define COMPACT_VALUES_164(fmt, value, ...) value, COMPACT_VALUES_162(__VA_ARGS__)
+#define COMPACT_VALUES_166(fmt, value, ...) value, COMPACT_VALUES_164(__VA_ARGS__)
+#define COMPACT_VALUES_168(fmt, value, ...) value, COMPACT_VALUES_166(__VA_ARGS__)
+#define COMPACT_VALUES_170(fmt, value, ...) value, COMPACT_VALUES_168(__VA_ARGS__)
+#define COMPACT_VALUES_172(fmt, value, ...) value, COMPACT_VALUES_170(__VA_ARGS__)
+#define COMPACT_VALUES_174(fmt, value, ...) value, COMPACT_VALUES_172(__VA_ARGS__)
+#define COMPACT_VALUES_176(fmt, value, ...) value, COMPACT_VALUES_174(__VA_ARGS__)
+#define COMPACT_VALUES_178(fmt, value, ...) value, COMPACT_VALUES_176(__VA_ARGS__)
+#define COMPACT_VALUES_180(fmt, value, ...) value, COMPACT_VALUES_178(__VA_ARGS__)
+#define COMPACT_VALUES_182(fmt, value, ...) value, COMPACT_VALUES_180(__VA_ARGS__)
+#define COMPACT_VALUES_184(fmt, value, ...) value, COMPACT_VALUES_182(__VA_ARGS__)
+#define COMPACT_VALUES_186(fmt, value, ...) value, COMPACT_VALUES_184(__VA_ARGS__)
+#define COMPACT_VALUES_188(fmt, value, ...) value, COMPACT_VALUES_186(__VA_ARGS__)
+#define COMPACT_VALUES_190(fmt, value, ...) value, COMPACT_VALUES_188(__VA_ARGS__)
+#define COMPACT_VALUES_192(fmt, value, ...) value, COMPACT_VALUES_190(__VA_ARGS__)
+#define COMPACT_VALUES_194(fmt, value, ...) value, COMPACT_VALUES_192(__VA_ARGS__)
+#define COMPACT_VALUES_196(fmt, value, ...) value, COMPACT_VALUES_194(__VA_ARGS__)
+#define COMPACT_VALUES_198(fmt, value, ...) value, COMPACT_VALUES_196(__VA_ARGS__)
+#define COMPACT_VALUES_200(fmt, value, ...) value, COMPACT_VALUES_198(__VA_ARGS__)
 
 #endif

src/io_threads.c

@@ -1,3 +1,9 @@
+/*
+ * Copyright Valkey Contributors.
+ * All rights reserved.
+ * SPDX-License-Identifier: BSD 3-Clause
+ */
+
 #include "io_threads.h"
 
 static __thread int thread_id = 0; /* Thread local var */
@@ -303,6 +309,8 @@ void initIOThreads(void) {
 
     serverAssert(server.io_threads_num <= IO_THREADS_MAX_NUM);
 
+    prefetchCommandsBatchInit();
+
     /* Spawn and initialize the I/O threads. */
     for (int i = 1; i < server.io_threads_num; i++) {
         createIOThread(i);

src/kvstore.c

@@ -93,7 +93,7 @@ typedef struct {
 /**********************************/
 
 /* Get the dictionary pointer based on dict-index. */
-static dict *kvstoreGetDict(kvstore *kvs, int didx) {
+dict *kvstoreGetDict(kvstore *kvs, int didx) {
     return kvs->dicts[didx];
 }
 

src/kvstore.h

@@ -76,5 +76,6 @@ void kvstoreDictSetVal(kvstore *kvs, int didx, dictEntry *de, void *val);
 dictEntry *kvstoreDictTwoPhaseUnlinkFind(kvstore *kvs, int didx, const void *key, dictEntry ***plink, int *table_index);
 void kvstoreDictTwoPhaseUnlinkFree(kvstore *kvs, int didx, dictEntry *he, dictEntry **plink, int table_index);
 int kvstoreDictDelete(kvstore *kvs, int didx, const void *key);
+dict *kvstoreGetDict(kvstore *kvs, int didx);
 
 #endif /* DICTARRAY_H_ */