is it ok?
1. it can be --disabled in evas's configure, but i think it works WITHOUT
disabling it (runtime) as it falls back to the old way of loading
2. it may cause build problems on some platforms - without it being enabled
we won't find out, so enable.
3. it needs enabling runtime to make use of it so it should be safe for now
until you enable it.
what is it?
it is a SHARED cache server - that means images loaded are loaded BY the
cache server (not by the actual process using evas). images are shared via
shared memory segments (shm_open + mmap). this means only 1 copy is in all
ram at any time - no matter how many processes need it , and its only loaded
once. also if another app has already loaded the same data - and its in the
cache or active hash, then another process needing the same stuff will avoid
the loads as it will just get instant replies from the cache of "image already
there". as it runs in its own process it can also time-out images from the
cache too.
right now you enable it by doing 2 things
1. run evas_cserve (it has cmd-line options to configure cache etc.
2. export EVAS_CSERVE=1 (im the environment of apps that should use the cache
server).
it works (for me) without crashes or problems. except for the following:
1. preloading doesnt work so its disabled if cserve is enabled. thisis
because the load threads interfere withthe unix comms socket causing
problems. this need to really change and have the cserve know about/do
preload and let the select() on the evas async events fd listen for the
unsolicited reply "load done". but it's not broken - simple preloads are
syncronous and forced if cserve is enabled (at build time).
2. if cserve is killed/crashes every app using it will have a bad day. baaad
day. so dont do it. also cserve may be vulnerable to apps crashing on it - it
may also exit with sigpipe. this needs fixing.
3. if the apps load using relative paths - this will break as it doesnt
account for the CWD of the client currently. will be fixed.
4. no way to change cache config runtime (yet)
5. no way to get internal cache state (yet).
6. if cache server exist - it wont clean up the shmem file nodes in /dev/shm
- it will clean on restart (remove the old junk). this needs fixing.
if you fine other issues - let me know.
things for the future:
1. now its a separate server.. the server could do async http etc. loads too
2. as a server it could monitor history of usage of files and images and
auto-pre-load files it knows historically are loaded then whose data is
immediately accessed.
3. the same infra could be used to share font loads (freetype and/or
fontconfig data).
4. ultimately being able to share rendered font glyphs will help a lot too.
5. it could, on its own, monitor "free memory" and when free memory runs
load, reduce cache size dynamically. (improving low memory situations).
6. it should get a gui to query cache state/contents and display visually.
this would be awesome to have a list of thumbnails that show whats in the
cache, how many referencesa they have, last active timestamps etc.
blah blah.
please let me know if the build is broken asap though as i will vanish
offline for a bit in about 24hrs...
SVN revision: 40478
Carsten Haitzler