Changeset 724

Timestamp:

02/25/08 16:56:45 (6 months ago)

Author:

dormando

Message:

Enable use of large memory pages (Trond Norbye) <Trond.Norbye@Sun.COM>

Initial support for solaris.

Files:

• trunk/server/configure.ac (modified) (1 diff)
• trunk/server/doc/memory_management.txt (modified) (2 diffs)
• trunk/server/memcached.c (modified) (6 diffs)
• trunk/server/slabs.c (modified) (5 diffs)
• trunk/server/slabs.h (modified) (1 diff)

trunk/server/configure.ac

@@ -200 +200 @@
-
-AC_CHECK_FUNCS(mlockall)
+AC_CHECK_FUNCS(getpagesizes)
+AC_CHECK_FUNCS(memcntl)
-
-AC_CONFIG_FILES(Makefile doc/Makefile)

trunk/server/doc/memory_management.txt

@@ +1 @@
+Date: Tue, 20 Feb 2008
+From: Trond Norbye <trond.norbye@sun.com>
+
+When started with -L memcached will try to enable large memory
+pages, and preallocate all memory up front. By using large memory
+pages memcached could reduce the number of TLB misses (depending
+on the access pattern), and hence improve performance. 
+
+See http://en.wikipedia.org/wiki/Translation_lookaside_buffer for
+a description of TLB.
+
-Date: Fri, 5 Sep 2003 20:31:03 +0300
-From: Anatoly Vorobey <mellon@pobox.com>
@@ -45 +56 @@
-that's at all possible) common sizes of objects that the clients
-of this particular installation of memcached are likely to store.
-
+
+
-off changing, in the "naive" list of sizes outlined above, the class
-of 128 bytes to something a bit higher (because the overhead of 

trunk/server/memcached.c

@@ -2694 +2694 @@
-           "-P <file>     save PID in <file>, only used with -d option\n"
-           "-f <factor>   chunk size growth factor, default 1.25\n"
-
+
+
+
+
+
+
+
+
+
+
+
-#ifdef USE_THREADS
-    printf("-t <num>      number of threads to use, default 4\n");
@@ -2805 +2815 @@
-}
-
+#if defined(HAVE_GETPAGESIZES) && defined(HAVE_MEMCNTL)
+/*
+ * On systems that supports multiple page sizes we may reduce the
+ * number of TLB-misses by using the biggest available page size
+ */
+int enable_large_pages(void) {
+    int ret = -1;
+    size_t sizes[32];
+    int avail = getpagesizes(sizes, 32);
+    if (avail != -1) {
+        size_t max = sizes[0];
+        struct memcntl_mha arg = {0};
+        int ii;
+
+        for (ii = 1; ii < avail; ++ii) {
+            if (max < sizes[ii]) {
+                max = sizes[ii];
+            }
+        }
+
+        arg.mha_flags   = 0;
+        arg.mha_pagesize = max;
+        arg.mha_cmd = MHA_MAPSIZE_BSSBRK;
+
+        if (memcntl(0, 0, MC_HAT_ADVISE, (caddr_t)&arg, 0, 0) == -1) {
+            fprintf(stderr, "Failed to set large pages: %s\n",
+                    strerror(errno));
+            fprintf(stderr, "Will use default page size\n");
+        } else {
+            ret = 0;
+        }
+    } else {
+        fprintf(stderr, "Failed to get supported pagesizes: %s\n",
+                strerror(errno));
+        fprintf(stderr, "Will use default page size\n");
+    }
+
+    return ret;
+}
+#endif
+
-int main (int argc, char **argv) {
-    int c;
@@ -2810 +2861 @@
-    bool lock_memory = false;
-    bool daemonize = false;
+    bool preallocate = false;
-    int maxcore = 0;
-    char *username = NULL;
@@ -2834 +2886 @@
-
-    /* process arguments */
-
+L
-        switch (c) {
-        case 'a':
@@ -2918 +2970 @@
-            settings.detail_enabled = 1;
-            break;
+#if defined(HAVE_GETPAGESIZES) && defined(HAVE_MEMCNTL)
+        case 'L' :
+            if (enable_large_pages() == 0) {
+                preallocate = true;
+            }
+            break;
+#endif
-        default:
-            fprintf(stderr, "Illegal argument \"%c\"\n", c);
@@ -3057 +3116 @@
-    /* Hacky suffix buffers. */
-    suffix_init();
-
+, preallocate
-
-    /* managed instance? alloc and zero a bucket array */

trunk/server/slabs.c

@@ -55 +55 @@
-static int power_largest;
-
+static void *mem_base = NULL;
+static void *mem_current = NULL;
+static size_t mem_avail = 0;
+
-/*
- * Forward Declarations
- */
-static int do_slabs_newslab(const unsigned int id);
+static void *memory_allocate(size_t size);
-
-#ifndef DONT_PREALLOC_SLABS
@@ -93 +98 @@
- * accordingly.
- */
-
+, const bool prealloc
-    int i = POWER_SMALLEST - 1;
-    unsigned int size = sizeof(item) + settings.chunk_size;
@@ -102 +107 @@
-
-    mem_limit = limit;
+
+    if (prealloc) {
+        /* Allocate everything in a big chunk with malloc */
+        mem_base = malloc(mem_limit);
+        if (mem_base != NULL) {
+            mem_current = mem_base;
+            mem_avail = mem_limit;
+        } else {
+            fprintf(stderr, "Warning: Failed to allocate requested memory in"
+                    " one large chunk.\nWill allocate in smaller chunks\n");
+        }
+    }
+
-    memset(slabclass, 0, sizeof(slabclass));
-
@@ -188 +206 @@
-    if (grow_slab_list(id) == 0) return 0;
-
-alloc
+emory_allocate
-    if (ptr == 0) return 0;
-
@@ -375 +393 @@
-}
-#endif
+
+static void *memory_allocate(size_t size) {
+    void *ret;
+
+    if (mem_base == NULL) {
+        /* We are not using a preallocated large memory chunk */
+        ret = malloc(size);
+    } else {
+        ret = mem_current;
+
+        if (size > mem_avail) {
+            return NULL;
+        }
+
+        /* mem_current pointer _must_ be aligned!!! */
+        if (size % CHUNK_ALIGN_BYTES) {
+            size += CHUNK_ALIGN_BYTES - (size % CHUNK_ALIGN_BYTES);
+        }
+
+        mem_current += size;
+        if (size < mem_avail) {
+            mem_avail -= size;
+        } else {
+            mem_avail = 0;
+        }
+    }
+
+    return ret;
+}

trunk/server/slabs.h

@@ -3 +3 @@
-/** Init the subsystem. 1st argument is the limit on no. of bytes to allocate,
-    0 if no limit. 2nd argument is the growth factor; each slab will use a chunk
-
-
+
+
+
+
+
-
-