WIP support nvidia power management

src/modules/graphics.lua

@@ -3,7 +3,7 @@ local i_o			= require 'i_o'
 
 return function(update_freq, config, common, width, point)
    local NA = 'N/A'
-   local NVIDIA_EXE = 'nvidia-settings'
+   local NVIDIA_EXE = 'nvidia-smi'
 
    local geo = config.geometry
    local sep_spacing = geo.sep_spacing
@@ -22,29 +22,17 @@ return function(update_freq, config, common, width, point)
 
    -- vars to process the nv settings glob
    --
-   -- glob will be of the form:
-   --   <used_mem>
-   --   <total_mem>
-   --   <temp>
-   --   <gpu_freq>,<mem_freq>
-   --   graphics=<gpu_util>, memory=<mem_util>, video=<vid_util>, PCIe=<pci_util>
-   local NV_QUERY = NVIDIA_EXE..
-      ' -t'..
-      ' -q UsedDedicatedGPUmemory'..
-      ' -q TotalDedicatedGPUmemory'..
-      ' -q ThermalSensorReading'..
-      ' -q [gpu:0]/GPUCurrentClockFreqs'..
-      ' -q [gpu:0]/GPUutilization'..
-      ' 2>/dev/null'
 
-   local NV_REGEX = '(%d+)\n'..
-      '(%d+)\n'..
-      '(%d+)\n'..
-      '(%d+),(%d+)\n'..
-      'graphics=(%d+), memory=%d+, video=(%d+), PCIe=%d+\n'
+   local NV_QUERY = NVIDIA_EXE..
+      ' --query-gpu=memory.used,memory.total,temperature.gpu,clocks.gr,clocks.mem,utilization.gpu,utilization.decoder'..
+      ' --format=csv,noheader,nounits'
+
+   local NV_REGEX = '(%d+), (%d+), (%d+), (%d+), (%d+), (%d+), (%d+)'
 
    local mod_state = {
       error = false,
+      gpu_frequency = 0,
+      memory_frequency = 0,
       used_memory = 0,
       total_memory = 0,
       temp_reading = 0,
@@ -52,6 +40,11 @@ return function(update_freq, config, common, width, point)
       vid_utilization = 0
    }
 
+   local sleep_token = 0
+   local sleep_limit = 10
+   local gpu_idle_freq_limit = 250
+
+   -- TODO ensure this file exists
    local runtime_status_file = config.dev_power..'/runtime_status'
 
    local want_nvidia_query = config.show_temp or config.show_clock
@@ -59,7 +52,28 @@ return function(update_freq, config, common, width, point)
 
    local update_state = function()
       local is_active = i_o.read_file(runtime_status_file, nil, '*l') == 'active'
-      if is_active and want_nvidia_query then
+      -- this will make the nvidia-smi query fire only so often when the clock
+      -- is below a certain threshold. This is necessary to get the GPU to
+      -- suspend when nothing is 'using' it, at the cost of lowering the
+      -- response time for when it eventually is used again. Maybe won't
+      -- matter that much since the jobs that use the GPU tend to be long
+      -- anyways, so a few seconds won't hurt. Furthermore, there are ways to
+      -- wake this up manually by detecting certain processes the likely will
+      -- use the GPU (ffmpeg and friends) or detecting processes that are
+      -- holding /dev/nvidia* files (which isn't foolproof but it will capture
+      -- most events)
+      if is_active and
+         mod_state.gpu_frequency > 0 and
+         mod_state.gpu_frequency < gpu_idle_freq_limit then
+         if sleep_token < sleep_limit - 1 then
+            sleep_token = sleep_token + 1
+         else
+            sleep_token = 0
+         end
+      else
+         sleep_token = 0
+      end
+      if is_active and want_nvidia_query and sleep_token == 0 then
          local nvidia_settings_glob = i_o.execute_cmd(NV_QUERY)
          if nvidia_settings_glob == nil then
             mod_state.error = 'Error'
@@ -72,11 +86,13 @@ return function(update_freq, config, common, width, point)
                mod_state.gpu_utilization,
                mod_state.vid_utilization
                = __string_match(nvidia_settings_glob, NV_REGEX)
+            mod_state.gpu_frequency = tonumber(mod_state.gpu_frequency)
             mod_state.error = false
          end
       elseif is_active then
          mod_state.error = false
       else
+         mod_state.gpu_frequency = 0
          mod_state.error = 'Off'
       end
    end