powertop shows 40 wakeups/second for owfs, sensor sampling is only every 10 seconds

Question

I am running owfs (1-wire file system) and some other process samples the temperature data only every 10 seconds. Now powertop on that linux box shows 40 to 50 wakeup events per seconds for the owfs process. I assume that owfs goes out frequently to poll/sample the sensors which is why I see these wakeups.

Since I am very keen on energy consumption on this little machine (every little saving helps), I wonder if there is a way to reduce this wakeup frequency.

Answer 1

If you start owhttpd and browse port :2121 on the host you will see there is a page with timeout settings.

You can try to tweak the settings and once you are happy, put it in the owfs.conf file. I have not done this but it should work.

Here are the settings/timeout options listed on my network:

directory
          60

ftp 
         900

ha7 
          60

network 
           1

presence    
         120

serial  
           5

server  
          10

stable  
         300

uncached    
           5

volatile    
          15

w1  
          30

# Timeouts (all in seconds) 
# cache for values that change on their own  timeout_volatile = value 
# seconds "volatile" values remain in cache 
# cache for values that change on command  timeout_stable = value 
# seconds "stable" values remain in cache 
# cache for directory lists (non-alarm)  timeout_directory = value 
# seconds "directory" values remain in cache 
# cache for 1-wire device location  timeout_presence = value 
# seconds "device presence" (which bus)  timeout_serial = value 
# seconds to wait for serial response  timeout_usb = value 
# seconds to wait for USB response  timeout_network = value 
# seconds to wait for tcp/ip response  timeout_ftp = value 
# seconds inactivity before closing ftp session