Add page caching mechanism.
The pages are stored in the cache ordered by their address.
Signed-off-by: Orit Wasserman <owass...@redhat.com>
---
arch_init.c | 183 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 183 insertions(+), 0 deletions(-)
diff --git a/arch_init.c b/arch_init.c
index d4c92b0..fdda277 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -28,6 +28,7 @@
#include <sys/types.h>
#include <sys/mman.h>
#endif
+#include <assert.h>
#include "config.h"
#include "monitor.h"
#include "sysemu.h"
@@ -42,6 +43,14 @@
#include "gdbstub.h"
#include "hw/smbios.h"
+#ifdef DEBUG_ARCH_INIT
+#define DPRINTF(fmt, ...) \
+ do { fprintf(stdout, "arch_init: " fmt, ## __VA_ARGS__); } while (0)
+#else
+#define DPRINTF(fmt, ...) \
+ do { } while (0)
+#endif
+
#ifdef TARGET_SPARC
int graphic_width = 1024;
int graphic_height = 768;
@@ -94,6 +103,180 @@ const uint32_t arch_type = QEMU_ARCH;
#define RAM_SAVE_FLAG_EOS 0x10
#define RAM_SAVE_FLAG_CONTINUE 0x20
+/***********************************************************/
+/* Page cache for storing previous pages as basis for XBRLE compression */
+#define CACHE_N_WAY 2 /* 2-way assossiative cache */
+
+typedef struct CacheItem {
+ ram_addr_t it_addr;
+ unsigned long it_age;
+ uint8_t *it_data;
+} CacheItem;
+
+typedef struct CacheBucket {
+ CacheItem bkt_item[CACHE_N_WAY];
+} CacheBucket;
+
+static CacheBucket *page_cache;
+static int64_t cache_num_buckets;
+static uint64_t cache_max_item_age;
+static int64_t cache_num_items;
+
+static void cache_init(ssize_t num_buckets);
+static void cache_fini(void);
+static int cache_is_cached(ram_addr_t addr);
+static int cache_get_oldest(CacheBucket *buck);
+static int cache_get_newest(CacheBucket *buck, ram_addr_t addr);
+static void cache_insert(ram_addr_t id, uint8_t *pdata);
+static unsigned long cache_get_cache_pos(ram_addr_t address);
+static CacheItem *cache_item_get(unsigned long pos, int item);
+
+/***********************************************************/
+/* XBRLE (Xor Based Run-Length Encoding) */
+typedef struct XBRLEHeader {
+ uint8_t xh_flags;
+ uint16_t xh_len;
+ uint32_t xh_cksum;
+} XBRLEHeader;
+
+/***********************************************************/
+/* XBRLE page cache implementation */
+static CacheItem *cache_item_get(unsigned long pos, int item)
+{
+ assert(page_cache);
+ return &page_cache[pos].bkt_item[item];
+}
+
+static void cache_init(int64_t num_bytes)
+{
+ int i;
+
+ cache_num_items = 0;
+ cache_max_item_age = 0;
+ cache_num_buckets = num_bytes / (TARGET_PAGE_SIZE * CACHE_N_WAY);
+ assert(cache_num_buckets);
+ DPRINTF("Setting cache buckets to %lu\n", cache_num_buckets);
+
+ assert(!page_cache);
+ page_cache = (CacheBucket *)g_malloc0((cache_num_buckets) *
+ sizeof(CacheBucket));
+
+ for (i = 0; i < cache_num_buckets; i++) {
+ int j;
+ for (j = 0; j < CACHE_N_WAY; j++) {
+ CacheItem *it = cache_item_get(i, j);
+ it->it_data = NULL;
+ it->it_age = 0;
+ it->it_addr = -1;
+ }
+ }
+}
+
+static void cache_fini(void)
+{
+ int i;
+
+ assert(page_cache);
+
+ for (i = 0; i < cache_num_buckets; i++) {
+ int j;
+ for (j = 0; j < CACHE_N_WAY; j++) {
+ CacheItem *it = cache_item_get(i, j);
+ g_free(it->it_data);
+ it->it_data = 0;
+ }
+ }
+
+ g_free(page_cache);
+ page_cache = NULL;
+}
+
+static unsigned long cache_get_cache_pos(ram_addr_t address)
+{
+ unsigned long pos;
+
+ assert(cache_num_buckets);
+ pos = (address/TARGET_PAGE_SIZE) & (cache_num_buckets - 1);
+ return pos;
+}
+
+static int cache_get_newest(CacheBucket *buck, ram_addr_t addr)
+{
+ unsigned long big = 0;
+ int big_pos = -1;
+ int j;
+
+ assert(page_cache);
+
+ for (j = 0; j < CACHE_N_WAY; j++) {
+ CacheItem *it = &buck->bkt_item[j];
+
+ if (it->it_addr != addr) {
+ continue;
+ }
+
+ if (!j || it->it_age > big) {
+ big = it->it_age;
+ big_pos = j;
+ }
+ }
+
+ return big_pos;
+}
+
+static int cache_get_oldest(CacheBucket *buck)
+{
+ unsigned long small = 0;
+ int small_pos = -1;
+ int j;
+
+ assert(page_cache);
+
+ for (j = 0; j < CACHE_N_WAY; j++) {
+ CacheItem *it = &buck->bkt_item[j];
+
+ if (!j || it->it_age < small) {
+ small = it->it_age;
+ small_pos = j;
+ }
+ }
+
+ return small_pos;
+}
+
+static int cache_is_cached(ram_addr_t addr)
+{
+ unsigned long pos = cache_get_cache_pos(addr);
+
+ assert(page_cache);
+ CacheBucket *bucket = &page_cache[pos];
+ return cache_get_newest(bucket, addr);
+}
+
+static void cache_insert(unsigned long addr, uint8_t *pdata)
+{
+ unsigned long pos;
+ int slot = -1;
+ CacheBucket *bucket;
+
+ pos = cache_get_cache_pos(addr);
+ assert(page_cache);
+ bucket = &page_cache[pos];
+ slot = cache_get_oldest(bucket); /* evict LRU */
+
+ /* actual update of entry */
+ CacheItem *it = cache_item_get(pos, slot);
+ if (!it->it_data) {
+ cache_num_items++;
+ }
+ g_free(it->it_data);
+
+ it->it_data = g_malloc0(TARGET_PAGE_SIZE);
+ memcpy(it->it_data, pdata, TARGET_PAGE_SIZE);
+ it->it_age = ++cache_max_item_age;
+ it->it_addr = addr;
+}
+
static int is_dup_page(uint8_t *page, uint8_t ch)
{
uint32_t val = ch << 24 | ch << 16 | ch << 8 | ch;
--
1.7.6.5
