Move time formatting routines in the Time module

src/Streamly/SVar.hs

@@ -134,9 +134,8 @@ import GHC.IO (IO(..))
 import Streamly.Time.Clock (Clock(..), getTime)
 import Streamly.Time.Units
        (AbsTime, NanoSecond64(..), MicroSecond64(..), diffAbsTime64,
-        fromRelTime64, toRelTime64)
+        fromRelTime64, toRelTime64, showNanoSecond64, showRelTime64)
 import System.IO (hPutStrLn, stderr)
-import Text.Printf (printf)
 
 import qualified Data.Heap as H
 import qualified Data.Set                    as S
@@ -643,31 +642,6 @@ collectLatency sv yinfo drain = do
 -- Dumping the SVar for debug/diag
 -------------------------------------------------------------------------------
 
--- | Convert a number of seconds to a string.  The string will consist
--- of four decimal places, followed by a short description of the time
--- units.
-secs :: Double -> String
-secs k
-    | k < 0      = '-' : secs (-k)
-    | k >= 1     = k        `with` "s"
-    | k >= 1e-3  = (k*1e3)  `with` "ms"
-#ifdef mingw32_HOST_OS
-    | k >= 1e-6  = (k*1e6)  `with` "us"
-#else
-    | k >= 1e-6  = (k*1e6)  `with` "μs"
-#endif
-    | k >= 1e-9  = (k*1e9)  `with` "ns"
-    | k >= 1e-12 = (k*1e12) `with` "ps"
-    | k >= 1e-15 = (k*1e15) `with` "fs"
-    | k >= 1e-18 = (k*1e18) `with` "as"
-    | otherwise  = printf "%g s" k
-     where with (t :: Double) (u :: String)
-               | t >= 1e9  = printf "%.4g %s" t u
-               | t >= 1e3  = printf "%.0f %s" t u
-               | t >= 1e2  = printf "%.1f %s" t u
-               | t >= 1e1  = printf "%.2f %s" t u
-               | otherwise = printf "%.3f %s" t u
-
 dumpSVarStats :: SVar t m a -> SVarStats -> SVarStyle -> IO String
 dumpSVarStats sv ss style = do
     case yieldRateInfo sv of
@@ -709,21 +683,17 @@ dumpSVarStats sv ss style = do
                then "\nheap max size = " <> show maxHp
                else "")
             <> (if minLat > 0
-               then "\nmin worker latency = "
-                    <> secs (fromIntegral minLat * 1e-9)
+               then "\nmin worker latency = " <> showNanoSecond64 minLat
                else "")
             <> (if maxLat > 0
-               then "\nmax worker latency = "
-                    <> secs (fromIntegral maxLat * 1e-9)
+               then "\nmax worker latency = " <> showNanoSecond64 maxLat
                else "")
             <> (if avgCnt > 0
                 then let lat = avgTime `div` fromIntegral avgCnt
-                     in "\navg worker latency = "
-                        <> secs (fromIntegral lat * 1e-9)
+                     in "\navg worker latency = " <> showNanoSecond64 lat
                 else "")
             <> (if svarLat > 0
-               then "\nSVar latency = "
-                        <> secs (fromIntegral svarLat * 1e-9)
+               then "\nSVar latency = " <> showRelTime64 svarLat
                else "")
             <> (if svarCnt > 0
                then "\nSVar yield count = " <> show svarCnt

src/Streamly/Time/Units.hs

@@ -1,5 +1,6 @@
 {-# LANGUAGE CPP #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE ScopedTypeVariables        #-}
 
 #include "inline.hs"
 
@@ -24,6 +25,7 @@ module Streamly.Time.Units
     , NanoSecond64(..)
     , MicroSecond64(..)
     , MilliSecond64(..)
+    , showNanoSecond64
 
     -- * Absolute times (using TimeSpec)
     , AbsTime(..)
@@ -43,10 +45,12 @@ module Streamly.Time.Units
     , fromRelTime64
     , diffAbsTime64
     , addToAbsTime64
+    , showRelTime64
     )
 where
 
 import Data.Int
+import Text.Printf (printf)
 
 -------------------------------------------------------------------------------
 -- Some constants
@@ -68,11 +72,25 @@ tenPower9 = 1000000000
 -- Time Unit Representations
 -------------------------------------------------------------------------------
 
+-- XXX We should be able to use type families to use different represenations
+-- for a unit.
+--
+-- Second Rational
+-- Second Double
+-- Second Int64
+-- Second Integer
+-- NanoSecond Int64
+-- ...
+
 -- Double or Fixed would be a much better representation so that we do not lose
 -- information between conversions. However, for faster arithmetic operations
 -- we use an 'Int64' here. When we need convservation of values we can use a
 -- different system of units with a Fixed precision.
---
+
+-------------------------------------------------------------------------------
+-- Integral Units
+-------------------------------------------------------------------------------
+
 -- | An 'Int64' time representation with a nanosecond resolution. It can
 -- represent time up to ~292 years.
 newtype NanoSecond64 = NanoSecond64 Int64
@@ -115,6 +133,10 @@ newtype MilliSecond64 = MilliSecond64 Int64
              , Ord
              )
 
+-------------------------------------------------------------------------------
+-- Fractional Units
+-------------------------------------------------------------------------------
+
 -------------------------------------------------------------------------------
 -- TimeSpec representation
 -------------------------------------------------------------------------------
@@ -403,3 +425,47 @@ diffAbsTime (AbsTime t1) (AbsTime t2) = RelTime (t1 - t2)
 {-# INLINE addToAbsTime #-}
 addToAbsTime :: AbsTime -> RelTime -> AbsTime
 addToAbsTime (AbsTime t1) (RelTime t2) = AbsTime $ t1 + t2
+
+-------------------------------------------------------------------------------
+-- Formatting and printing
+-------------------------------------------------------------------------------
+
+-- | Convert nanoseconds to a string showing time in an appropriate unit.
+showNanoSecond64 :: NanoSecond64 -> String
+showNanoSecond64 time@(NanoSecond64 ns)
+    | time < 0    = '-' : showNanoSecond64 (-time)
+    | ns < 1000 = fromIntegral ns `with` "ns"
+#ifdef mingw32_HOST_OS
+    | ns < 1000000 = (fromIntegral ns / 1000) `with` "us"
+#else
+    | ns < 1000000 = (fromIntegral ns / 1000) `with` "μs"
+#endif
+    | ns < 1000000000 = (fromIntegral ns / 1000000) `with` "ms"
+    | ns < (60 * 1000000000) = (fromIntegral ns / 1000000000) `with` "s"
+    | ns < (60 * 60 * 1000000000) =
+        (fromIntegral ns / (60 * 1000000000)) `with` "min"
+    | ns < (24 * 60 * 60 * 1000000000) =
+        (fromIntegral ns / (60 * 60 * 1000000000)) `with` "hr"
+    | ns < (365 * 24 * 60 * 60 * 1000000000) =
+        (fromIntegral ns / (24 * 60 * 60 * 1000000000)) `with` "days"
+    | otherwise =
+        (fromIntegral ns / (365 * 24 * 60 * 60 * 1000000000)) `with` "years"
+     where with (t :: Double) (u :: String)
+               | t >= 1e9  = printf "%.4g %s" t u
+               | t >= 1e3  = printf "%.0f %s" t u
+               | t >= 1e2  = printf "%.1f %s" t u
+               | t >= 1e1  = printf "%.2f %s" t u
+               | otherwise = printf "%.3f %s" t u
+
+-- In general we should be able to show the time in a specified unit, if we
+-- omit the unit we can show it in an automatically chosen one.
+{-
+data UnitName =
+      Nano
+    | Micro
+    | Milli
+    | Sec
+-}
+
+showRelTime64 :: RelTime64 -> String
+showRelTime64 = showNanoSecond64 . fromRelTime64