From a0397ad2ad0f9382bccf4e10ecf1435dab9cf01c Mon Sep 17 00:00:00 2001
From: "Robert J. Macomber" <robertm@dilithium>
Date: Fri, 27 Jun 2014 18:22:30 -0700
Subject: Fix for CPU monitor on long-running systems

After running long enough, the numbers in /proc/stat get big enough
that they will not fit in a Float without loss of precision, which
leads to erratic results such as reporting "NaN%" CPU usage.

This commit simply keeps the numbers integral until producing the final
percentage result.
---
 src/Plugins/Monitors/Cpu.hs | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/Plugins/Monitors/Cpu.hs b/src/Plugins/Monitors/Cpu.hs
index 6e83c67..df2dc4e 100644
--- a/src/Plugins/Monitors/Cpu.hs
+++ b/src/Plugins/Monitors/Cpu.hs
@@ -24,12 +24,12 @@ cpuConfig = mkMConfig
        "Cpu: <total>%"
        ["bar","vbar","total","user","nice","system","idle","iowait"]
 
-type CpuDataRef = IORef [Float]
+type CpuDataRef = IORef [Int]
 
-cpuData :: IO [Float]
+cpuData :: IO [Int]
 cpuData = cpuParser `fmap` B.readFile "/proc/stat"
 
-cpuParser :: B.ByteString -> [Float]
+cpuParser :: B.ByteString -> [Int]
 cpuParser = map (read . B.unpack) . tail . B.words . head . B.lines
 
 parseCpu :: CpuDataRef -> IO [Float]
@@ -38,8 +38,8 @@ parseCpu cref =
        b <- cpuData
        writeIORef cref b
        let dif = zipWith (-) b a
-           tot = foldr (+) 0 dif
-           percent = map (/ tot) dif
+           tot = fromIntegral $ foldr (+) 0 dif
+           percent = map (/ tot) (map fromIntegral dif)
        return percent
 
 formatCpu :: [Float] -> Monitor [String]
-- 
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