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authorSibi Prabakaran <sibi@psibi.in>2020-06-05 16:55:52 +0530
committerSibi Prabakaran <sibi@psibi.in>2020-06-05 16:55:52 +0530
commit878db39080607ba476ba8d8f547ad28259efb6a9 (patch)
tree2458ce512885d6ca527e14e9c8751458e4afe320 /src
parentb15bb7c20b11a9f148c4757caba7167ee66492fc (diff)
downloadxmobar-878db39080607ba476ba8d8f547ad28259efb6a9.tar.gz
xmobar-878db39080607ba476ba8d8f547ad28259efb6a9.tar.bz2
Optimize date plugin
We avoid calling getTimeZone for each of the time the date has to be updated. Instead, it's computed once at the start and re-used for each invocation. Looking at the implementation of 'getTimeZone', we can see that it's very expensive: https://www.stackage.org/haddock/lts-15.15/time-1.9.3/src/Data-Time-LocalTime-Internal-TimeZone.html#getTimeZone It calls a C FFI each time to get the time zone (getTimeZoneCTime). This is something which we can avoid and the MR implements that. I have been using my xmobar with this patch and the result has been quite good. My xmobar CPU usage has used to hit 3~7% intermittently. With this MR, It hits only 0.7% intermittently which is nice. :-)
Diffstat (limited to 'src')
-rw-r--r--src/Xmobar/Plugins/Date.hs14
1 files changed, 11 insertions, 3 deletions
diff --git a/src/Xmobar/Plugins/Date.hs b/src/Xmobar/Plugins/Date.hs
index 1cb0596..83ca1c9 100644
--- a/src/Xmobar/Plugins/Date.hs
+++ b/src/Xmobar/Plugins/Date.hs
@@ -31,8 +31,16 @@ data Date = Date String String Int
instance Exec Date where
alias (Date _ a _) = a
- run (Date f _ _) = date f
rate (Date _ _ r) = r
+ start (Date f _ r) cb = do
+ t <- getCurrentTime
+ zone <- getTimeZone t
+ go zone
+ where
+ go zone = doEveryTenthSeconds r $ date zone f >>= cb
-date :: String -> IO String
-date format = fmap (formatTime defaultTimeLocale format) getZonedTime
+date :: TimeZone -> String -> IO String
+date timezone format = do
+ time <- getCurrentTime
+ let zonedTime = utcToZonedTime timezone time
+ pure $ formatTime defaultTimeLocale format zonedTime