pic use memcache as a RAM memory first i lock memcache (with my today lock function) set a key to 0 i read data from pic, and put at memcache after 128 writes i put a sum (save this sum at pic internal memory) total bytes is about 1MB(1048576 bytes) (pic don't have this memory, it's a ADC read 2Bytes/read) after all 1MB sent, i check all sums with my internal memory, to make sure some data wasn't lost if lost, i start a new lock set a key to 1 after it, i unlock memcache (my today unlock function) wait just some minutes if get set isn't 2 return to first lock if 2 continue with another function inside pic program
after key=1 my server (another app), process and set key to 2 if ok i'm using memcache as a key-value and as a server-client protocol ok it's not fast, but it's work the other implementation use a server side, and a ARM client side server don't use more memcache, ARM doesn't use it too, i'm using mysql at ARM side and tcp/ip socket to contact my app about new data (it's faster than a table update in mysql) 2011/2/5 dormando <dorma...@rydia.net>: >> problem: >> today i need 4 packets to make 'lock'/'unlock' using memcache >> i need to use less ROM/CPU/RAM/network at client side >> >> solution: >> 1) make server side lock function with 2 packet (with atomic operations) >> 2) make a proxy if function = lock/unlock, proxy make these packets to >> server (i don't have atomic here, but i can implement with a big work >> on protocol, maybe a new memcached hehe) >> >> i will try the second one without atomic (today i'm using it, i have >> some problems, but client side workaround it with more packets... >> (retry) ) >> the first is better (i don't need a proxy, i have less packets, use >> less cpu, ram, rom, time) >> >> packets: >> LOCK >> add value (1 packet sent by client, 1 packet sent by server) >> if no error (end here) >> if value exist >> read value (1packet sent by client, 1 packet sent by server) >> if value=my value (my lock) if not (not my lock) >> >> UNLOCK >> read value (1packet sent by client, 1 packet sent by server) >> if value != my value >> (end here) >> delete value (1packet sent by client, 1 packet sent by server) >> (end here) > > I think he means to step back a bit, and describe what problem it is that > lead you to needing to access memcached from a PIC. > > ie; what is the specific work that the PIC is doing which needs > synchronization and perhaps repeated accesses to memcached? > -- Roberto Spadim Spadim Technology / SPAEmpresarial
