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canvas cache on server is inefficient (contains two entries only!)

Submitted by Yaniv Kaul

Assigned to Spice Bug List

Link to original bug (#37456)

Description

It appears there is some nice caching infrastructure for canvas in the server (regretfully called image_put and image_get (server/red_worker.c), but it contains only up to 2(!) entries (IMAGE_CACHE_MAX_ITEMS is defined as 2), making it completely useless. I changed it to contain more, and saw no issues with it. I did see XP guests use more entries when it was enabled. Linux (F15) guests did not use it anyway.

All that I've done to gather the above is sprinkle some red_printf()'s after reading the code:

[ykaul@ykaul spice]$ git diff server/red_worker.c diff --git a/server/red_worker.c b/server/red_worker.c index bee86b9..16bf4b6 100644 --- a/server/red_worker.c +++ b/server/red_worker.c @@ -3494,7 +3494,7 @@ static int image_cache_hit(ImageCache *cache, uint64_t id) static void image_cache_remove(ImageCache *cache, ImageCacheItem *item) { ImageCacheItem **now;

  • red_printf("id %lu, hash location: %lu", item->id, item->id % IMAGE_CACHE_HASH_SIZE); now = &cache->hash_table[item->id % IMAGE_CACHE_HASH_SIZE]; for (;;) { ASSERT(*now); @@ -3518,9 +3518,10 @@ static void image_cache_put(SpiceImageCache *spice_cache, uint64_t id, pixman_im { ImageCache *cache = (ImageCache *)spice_cache; ImageCacheItem *item;

#ifndef IMAGE_CACHE_AGE

  • red_printf("cache->num_items: %u", cache->num_items); if (cache->num_items == IMAGE_CACHE_MAX_ITEMS) {
  • red_printf("cache->num_items == IMAGE_CACHE_MAX_ITEMS !!!"); ImageCacheItem *tail = (ImageCacheItem *)ring_get_tail(&cache->lru); ASSERT(tail); image_cache_remove(cache, tail); @@ -3536,7 +3537,7 @@ static void image_cache_put(SpiceImageCache *spice_cache, uint64_t id, pixman_im #endif item->image = pixman_image_ref(image); ring_item_init(&item->lru_link);
  • red_printf("id %lu, hash location: %lu", item->id, item->id % IMAGE_CACHE_HASH_SIZE); item->next = cache->hash_table[item->id % IMAGE_CACHE_HASH_SIZE]; cache->hash_table[item->id % IMAGE_CACHE_HASH_SIZE] = item;

here's a run example: do_spice_init: ykaul: starting 0.6.3 spice_server_add_interface: SPICE_INTERFACE_KEYBOARD spice_server_add_interface: SPICE_INTERFACE_MOUSE spice_server_add_interface: SPICE_INTERFACE_QXL red_worker_main: begin spice_server_add_interface: SPICE_INTERFACE_PLAYBACK handle_dev_destroy_surfaces: handle_dev_destroy_surfaces: handle_dev_input: start QEMU 0.14.50 monitor - type 'help' for more information (qemu) handle_dev_destroy_surfaces: handle_dev_destroy_surfaces: reds_handle_read_link_done: Peer doesn't support AUTH selection reds_handle_main_link: reds_show_new_channel: channel 1:0, connected successfully, over Non Secure link main_channel_link: reds_handle_read_link_done: Peer doesn't support AUTH selection reds_show_new_channel: channel 4:0, connected successfully, over Non Secure link red_dispatcher_set_cursor_peer: main_channel_handle_parsed: net test: latency 0.260000 ms, bitrate 141221900 bps (134.679699 Mbps) handle_dev_input: cursor connect reds_handle_read_link_done: Peer doesn't support AUTH selection reds_show_new_channel: channel 5:0, connected successfully, over Non Secure link reds_handle_read_link_done: Peer doesn't support AUTH selection reds_show_new_channel: channel 2:0, connected successfully, over Non Secure link red_dispatcher_set_peer: handle_dev_input: connect handle_new_display_channel: jpeg disabled handle_new_display_channel: zlib-over-glz disabled image_cache_put: cache->num_items: 0 image_cache_put: id 16692984622346338345, hash location: 41 image_cache_put: cache->num_items: 1 image_cache_put: id 3280720828400402688, hash location: 256 image_cache_put: cache->num_items: 2 image_cache_put: cache->num_items == IMAGE_CACHE_MAX_ITEMS !!! image_cache_remove: id 16692984622346338345, hash location: 41 image_cache_put: id 9713389464692457571, hash location: 99 reds_handle_read_link_done: Peer doesn't support AUTH selection reds_show_new_channel: channel 3:0, connected successfully, over Non Secure link inputs_link: image_cache_put: cache->num_items: 2 image_cache_put: cache->num_items == IMAGE_CACHE_MAX_ITEMS !!! image_cache_remove: id 9713389464692457571, hash location: 99 image_cache_put: id 16692984622346338345, hash location: 41 image_cache_put: cache->num_items: 2 image_cache_put: cache->num_items == IMAGE_CACHE_MAX_ITEMS !!! image_cache_remove: id 16692984622346338345, hash location: 41 image_cache_put: id 9323874577061568761, hash location: 249 image_cache_put: cache->num_items: 2 image_cache_put: cache->num_items == IMAGE_CACHE_MAX_ITEMS !!! image_cache_remove: id 3280720828400402688, hash location: 256 image_cache_put: id 9713389464692457571, hash location: 99 image_cache_put: cache->num_items: 2 image_cache_put: cache->num_items == IMAGE_CACHE_MAX_ITEMS !!! image_cache_remove: id 9323874577061568761, hash location: 249 image_cache_put: id 10655197967897838368, hash location: 800 image_cache_put: cache->num_items: 2 image_cache_put: cache->num_items == IMAGE_CACHE_MAX_ITEMS !!! image_cache_remove: id 9713389464692457571, hash location: 99 image_cache_put: id 6355812529235034368, hash location: 256 image_cache_put: cache->num_items: 2 image_cache_put: cache->num_items == IMAGE_CACHE_MAX_ITEMS !!! image_cache_remove: id 10655197967897838368, hash location: 800 image_cache_put: id 17566795881926623488, hash location: 256 image_cache_put: cache->num_items: 2 image_cache_put: cache->num_items == IMAGE_CACHE_MAX_ITEMS !!! image_cache_remove: id 6355812529235034368, hash location: 256 image_cache_put: id 13707069709730971904, hash location: 256 image_cache_put: cache->num_items: 2 image_cache_put: cache->num_items == IMAGE_CACHE_MAX_ITEMS !!! image_cache_remove: id 17566795881926623488, hash location: 256 image_cache_put: id 1412022055884816640, hash location: 256 image_cache_put: cache->num_items: 2 image_cache_put: cache->num_items == IMAGE_CACHE_MAX_ITEMS !!! image_cache_remove: id 13707069709730971904, hash location: 256 image_cache_put: id 6355812529235034368, hash location: 256 image_cache_put: cache->num_items: 2 image_cache_put: cache->num_items == IMAGE_CACHE_MAX_ITEMS !!! image_cache_remove: id 1412022055884816640, hash location: 256 image_cache_put: id 7051416241264910410, hash location: 74 image_cache_put: cache->num_items: 2 image_cache_put: cache->num_items == IMAGE_CACHE_MAX_ITEMS !!! image_cache_remove: id 6355812529235034368, hash location: 256 image_cache_put: id 12743327117782106113, hash location: 1 image_cache_put: cache->num_items: 2 image_cache_put: cache->num_items == IMAGE_CACHE_MAX_ITEMS !!! image_cache_remove: id 7051416241264910410, hash location: 74 image_cache_put: id 3738288703970295809, hash location: 1 image_cache_put: cache->num_items: 2 image_cache_put: cache->num_items == IMAGE_CACHE_MAX_ITEMS !!! image_cache_remove: id 12743327117782106113, hash location: 1 image_cache_put: id 16714730741845475333, hash location: 5 image_cache_put: cache->num_items: 2 image_cache_put: cache->num_items == IMAGE_CACHE_MAX_ITEMS !!! image_cache_remove: id 3738288703970295809, hash location: 1 image_cache_put: id 12743327117782106113, hash location: 1