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author | Anton Vorontsov <anton@enomsg.org> | 2014-09-16 15:48:49 -0700 |
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committer | Anton Vorontsov <anton@enomsg.org> | 2014-09-16 20:20:10 -0700 |
commit | 73053ddf3386604f19b494afd9c234ac50427d6c (patch) | |
tree | 9b11fc330277073806b73be3c075659784e239ea | |
parent | a6933f49ae9bdc8cbd5bee42920e5b9a01c21e7f (diff) | |
download | xmobar-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.hs | 30 |
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 () |