reducing overhead for I/O lua code.

Plugins & Plugin Development General Plugin Discussion
1

Hi all
I am trying to reduce overhead in my plugin and one of the things that I have done is remove polling.

Below is based on guessed "state machine"IORelay plugin. Can any Lua experts tell me if there is a better way of doing this? I have tried to cut it down th the bare minimum to ensure that it is understandable.

[code]–Global values
writeQueue = {}
TIMEOUT = 1
local handler = nil
local handlerDevice
local handlerData
local handlerTime
DEBUG_MODE = true

local function log(text, level)

luup.log("Plugin: " .. text, (level or 1))

end

local function debug(text)

if (DEBUG_MODE == true) then
    log("debug: " .. text, 50)
end

end

local function processQueue()

--Process first command in queue.
local data = writeQueue[1]
if (data == nil) then
    return true
end

buffer = ""
handlerTime = os.time()
handler = data[2]
handlerDevice = data[3]
handlerData = data[4]

table.remove(writeQueue,1)

write(data[1])

return true

end

local function processData()

local t = os.time()

if (handler ~= nil) then
    if (t >= handlerTime + TIMEOUT) then
        log("poll: stale handler found, queue length:"..#writeQueue)
        return processQueue()
    end
    debug(string.format("processData: exiting, busy (entries=%i)", #writeQueue))
    return true
end

debug(string.format("processData: entering, free (entries=%i)", #writeQueue))

return processQueue()

end

local function queueData(data, handler, device, handlerData)

–insert into command queue
table.insert(writeQueue, {data, handler, device, handlerData})

    while #writeQueue > 0 do
        processData()
    end

end

function incomingData(lul_data)

–Incoming data handler.
local data = tostring(lul_data)
debug(string.format(“incoming: data=0x%02X”, data:byte(1)))

if (handler ~= nil) then
  if (handler(data, handlerDevice, handlerData) == false) then
    handler = nil
  end
else
  debug(string.format("incoming: No handler set to take data=0x%x", data:byte(1)))
end

end

[/code]
Thanks

Zoot

2

What format is the incoming data in, and can you use a native tokenizer instead of raw? (So that Versa gives you larger chunks in the incoming block)

3

The two plugins I am working with currently are both three bytes incoming no CR/LR (rain8net & DIDIO). So currently stuck with raw.

Both devices also need to be queried to return status which is a pita, I think in future I will try and buy semi-intelligent devices so that I can de-load my central controller.

regards

Zoot