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authorAnton Vorontsov <anton@enomsg.org>2014-09-16 15:48:49 -0700
committerAnton Vorontsov <anton@enomsg.org>2014-09-16 20:20:10 -0700
commit73053ddf3386604f19b494afd9c234ac50427d6c (patch)
tree9b11fc330277073806b73be3c075659784e239ea
parenta6933f49ae9bdc8cbd5bee42920e5b9a01c21e7f (diff)
downloadxmobar-73053ddf3386604f19b494afd9c234ac50427d6c.tar.gz
xmobar-73053ddf3386604f19b494afd9c234ac50427d6c.tar.bz2
Locks: Rework to avoid unnecessary display reopening
The extremely useful "Locks" plugin eats quite a lot of CPU (>2% here on a old-ish laptop), unfortunately. The plug-in unnecessary reopens the display, which is quite expensive operation. It results into 16 syscalls: socket(PF_LOCAL) -> connect(sun_path=@"/tmp/.X11-unix/X0"}) -> getpeername() -> uname() -> access(".Xauthority") -> open(".Xauthority") -> fstat() -> mmap() -> read() -> close() -> munmap() -> getsockname() -> fcntl(F_SETFD) -> fcntl(F_SETFL) -> shutdown() -> close() This is almost half of all the syscalls that we ought to execute for the plug-in to work. Now, considering the useful work and that "Locks" runs every 200 milliseconds, it gives us >300 syscalls (and a lot more wake-ups) per second. This commit fixes the reopening issue, effectively halving the CPU consumption (down to ~1%). The patch also makes it easier to implement event-driven indicators that will reduce the idle CPU consumption to 0.
-rw-r--r--src/Plugins/Locks.hs30
1 files changed, 19 insertions, 11 deletions
diff --git a/src/Plugins/Locks.hs b/src/Plugins/Locks.hs
index 3c1e0a9..b30eb1b 100644
--- a/src/Plugins/Locks.hs
+++ b/src/Plugins/Locks.hs
@@ -30,22 +30,30 @@ locks = [ ( xK_Caps_Lock, "CAPS" )
, ( xK_Scroll_Lock, "SCROLL" )
]
+run' :: Display -> Window -> IO String
+run' d root = do
+ modMap <- getModifierMapping d
+ ( _, _, _, _, _, _, _, m ) <- queryPointer d root
+
+ ls <- filterM ( \( ks, _ ) -> do
+ kc <- keysymToKeycode d ks
+ return $ case find (elem kc . snd) modMap of
+ Nothing -> False
+ Just ( i, _ ) -> testBit m (fromIntegral i)
+ ) locks
+
+ return $ unwords $ map snd ls
+
instance Exec Locks where
alias Locks = "locks"
rate Locks = 2
- run Locks = do
+ start Locks cb = do
d <- openDisplay ""
root <- rootWindow d (defaultScreen d)
- modMap <- getModifierMapping d
- ( _, _, _, _, _, _, _, m ) <- queryPointer d root
+ forever $ do
+ cb =<< run' d root
+ tenthSeconds $ rate Locks
- ls <- filterM ( \( ks, _ ) -> do
- kc <- keysymToKeycode d ks
- return $ case find (elem kc . snd) modMap of
- Nothing -> False
- Just ( i, _ ) -> testBit m (fromIntegral i)
- ) locks
closeDisplay d
-
- return $ unwords $ map snd ls
+ return ()