Use the "zone" feature for LuaJIT profiling.

Snabb Switch now tells the profiler what "zone" of computation is
executing at any given time. The profiler is then able to report on
each zone separately, when given the -jp=z flag.

The zone name for an app can be given explicitly as the "zone" field
of the app (or its class). If no name is given then one is guessed
based on the module name of the app's code.

Example output:

    # ./snabbswitch -jp=2zF -t apps.intel.intel_app
    75%  apps.intel.intel_app
      -- 18%  intel10g.lua:transmit < intel_app.lua:push
      -- 17%  intel10g.lua:receive < intel_app.lua:pull
      -- 11%  buffer.lua:free < packet.lua:free
      --  7%  intel10g.lua:sync_transmit < intel_app.lua:push
      --  5%  intel10g.lua:can_add_receive_buffer < intel_app.lua:add_receive_buffers
      --  4%  register.lua:RDH < intel10g.lua:sync_receive
      --  3%  freelist.lua:add < buffer.lua:free
      --  3%  intel10g.lua:add_receive_buffer < intel_app.lua:add_receive_buffers
      --  3%  link.lua:receive < intel_app.lua:push
      --  3%  link.lua:transmit < intel_app.lua:pull
      --  3%  freelist.lua:remove < packet.lua:allocate
    11%  Sink
      -- 48%  buffer.lua:free < packet.lua:free
      -- 13%  freelist.lua:add < packet.lua:free
      -- 11%  link.lua:receive < basic_apps.lua:push
      --  9%  freelist.lua:add < buffer.lua:free
      --  7%  packet.lua:free < packet.lua:deref
      --  7%  packet.lua:deref < basic_apps.lua:push
    10%  Source
      -- 45%  packet.lua:add_iovec < basic_apps.lua:pull
      -- 15%  link.lua:transmit < basic_apps.lua:pull
      -- 15%  freelist.lua:remove < buffer.lua:allocate
      -- 11%  link.lua:full < link.lua:transmit
      --  8%  freelist.lua:remove < packet.lua:allocate
      --  6%  basic_apps.lua:pull < app.lua:breathe
     4%  selftest
      -- 27%  lib.lua:waitfor < register.lua:wait
      -- 27%  memory.lua:allocate_RAM < memory.lua:allocate_next_chunk
      -- 23%  app.lua:breathe < app.lua:main
      -- 14%  zone.lua:zone < app.lua:breathe
      --  5%  lib.lua:firstline < pci.lua:device_info
      --  5%  lib.lua:done < app.lua:main

src/apps/basic/basic_apps.lua

@@ -22,7 +22,7 @@ end
 
 --- # `Source` app: generate synthetic packets
 
-Source = setmetatable({}, {__index = Basic})
+Source = setmetatable({zone = "Source"}, {__index = Basic})
 
 function Source:new()
    return setmetatable({}, {__index=Source})
@@ -40,7 +40,7 @@ end
 
 --- # `Join` app: Merge multiple inputs onto one output
 
-Join = setmetatable({}, {__index = Basic})
+Join = setmetatable({zone = "Join"}, {__index = Basic})
 
 function Join:new()
    return setmetatable({}, {__index=Join})
@@ -58,7 +58,7 @@ end
 
 -- For each input port, push packets onto outputs. When one output
 -- becomes full then continue with the next.
-Split = setmetatable({}, {__index = Basic})
+Split = setmetatable({zone = "Split"}, {__index = Basic})
 
 function Split:new ()
    return setmetatable({}, {__index=Split})
@@ -76,7 +76,7 @@ end
 
 --- ### `Sink` app: Receive and discard packets
 
-Sink = setmetatable({}, {__index = Basic})
+Sink = setmetatable({zone = "Sink"}, {__index = Basic})
 
 function Sink:new ()
    return setmetatable({}, {__index=Sink})
@@ -98,7 +98,7 @@ end
 -- Assumed to be used in pair with FastRepeater
 -- FastSink doesn't calculate rx statistics
 
-FastSink = setmetatable({}, {__index = Basic})
+FastSink = setmetatable({zone = "FastSink"}, {__index = Basic})
 
 function FastSink:new ()
    return setmetatable({}, {__index=Sink})
@@ -113,7 +113,7 @@ end
 
 --- ### `Tee` app: Send inputs to all outputs
 
-Tee = setmetatable({}, {__index = Basic})
+Tee = setmetatable({zone = "Tee"}, {__index = Basic})
 
 function Tee:new ()
    return setmetatable({}, {__index=Tee})
@@ -141,7 +141,7 @@ end
 
 --- ### `Repeater` app: Send all received packets in a loop
 
-Repeater = setmetatable({}, {__index = Basic})
+Repeater = setmetatable({zone = "Repeater"}, {__index = Basic})
 
 function Repeater:new ()
    return setmetatable({index = 1, packets = {}},
@@ -171,7 +171,7 @@ end
 -- Only for test purpose, never use it in real world application
 -- Assumed to be used in pair with FastSink
 
-FastRepeater = setmetatable({}, {__index = Basic})
+FastRepeater = setmetatable({zone = "FastRepeater"}, {__index = Basic})
 
 function FastRepeater:new ()
    return setmetatable({init = true},
@@ -211,7 +211,7 @@ end
 
 --- ### `Buzz` app: Print a debug message when called
 
-Buzz = setmetatable({}, {__index = Basic})
+Buzz = setmetatable({zone = "Buzz"}, {__index = Basic})
 
 function Buzz:new ()
    return setmetatable({}, {__index=Buzz})

src/core/app.lua

@@ -6,6 +6,7 @@ local lib    = require("core.lib")
 local link   = require("core.link")
 local config = require("core.config")
 local timer  = require("core.timer")
+local zone   = require("jit.zone")
 require("core.packet_h")
 
 -- The set of all active apps and links in the system.
@@ -67,11 +68,13 @@ function apply_config_actions (actions, conf)
       local class = conf.apps[name].class
       local arg = conf.apps[name].arg
       local app = class:new(arg)
+      local zone = app.zone or getfenv(class.new)._NAME or name
       app.output = {}
       app.input = {}
       new_app_table[name] = app
       table.insert(new_app_array, app)
       app_name_to_index[name] = #new_app_array
+      app.zone = zone
    end
    function ops.restart (name)
       ops.stop(name)
@@ -127,7 +130,9 @@ end
 function breathe ()
    -- Inhale: pull work into the app network
    for _, app in ipairs(app_array) do
-      if app.pull then app:pull() end
+      if app.pull then
+         zone(app.zone) app:pull() zone()
+      end
    end
    -- Exhale: push work out through the app network
    local firstloop = true
@@ -139,7 +144,7 @@ function breathe ()
             link.has_new_data = false
             local receiver = app_array[link.receiving_app]
             if receiver.push then
-               receiver:push()
+               zone(receiver.zone) receiver:push() zone()
                progress = true
             end
          end

src/core/main.lua

@@ -1,6 +1,7 @@
 module(...,package.seeall)
 
 local ffi = require("ffi")
+local zone = require("jit.zone")
 local C   = ffi.C
 
 require("lib.lua.strict")
@@ -30,6 +31,7 @@ local profiling = false
 parameters = {}
 
 function main ()
+   zone("startup")
    require "lib.lua.strict"
    initialize()
    local args = command_line_args()
@@ -43,7 +45,7 @@ function main ()
 	 require(args[i+1])
 	 i = i + 2
       elseif args[i] == '-t' and i < #args then
-         require(args[i+1]).selftest()
+         zone("selftest")  require(args[i+1]).selftest()  zone()
          i = i + 2
       elseif args[i] == '-e' and i < #args then
 	 local thunk, error = loadstring(args[i+1])
@@ -70,6 +72,7 @@ function main ()
             table.insert(parameters, args[i])
             i = i + 1
          end
+         zone("module "..module)
          require(module)
          exit(0)
       else