我在使用GHC 7.8.3和Yesod 1.4.9时遇到了小的CPU泄漏。
当我用time运行我的站点并在1分钟后停止它(Ctrl+C)而不做任何事情(只是运行，根本没有请求)，它消耗1秒。约占CPU的1.7%。
$ time mysite
^C
real 1m0.226s
user 0m1.024s
sys 0m0.060s
如果我禁用空闲垃圾收集器，它将下降到0.35秒(0.6%的CPU)。虽然它更好，但它仍然不做任何事情就消耗CPU。
$ time mysite +RTS -I0 # Disable idle GC
^C
real 1m0.519s
user 0m0.352s
sys 0m0.064s
$ time mysite +RTS -I0
^C
real 4m0.676s
user 0m0.888s
sys 0m0.468s
$ time mysite +RTS -I0
^C
real 7m28.282s
user 0m1.452s
sys 0m0.976s
与cat命令无限期地等待标准输入上的某些内容相比:
$ time cat
^C
real 1m1.349s
user 0m0.000s
sys 0m0.000s
在Haskell中还有其他东西在后台消耗CPU吗?
是Yesod的泄漏吗?
还是我在程序中做了什么?(我只添加了处理函数，我不做并行计算)
编辑2015-05-31 19:25
下面是-s标志的执行:
$ time mysite +RTS -I0 -s
^C 23,138,184 bytes allocated in the heap
4,422,096 bytes copied during GC
2,319,960 bytes maximum residency (4 sample(s))
210,584 bytes maximum slop
6 MB total memory in use (0 MB lost due to fragmentation)
Tot time (elapsed) Avg pause Max pause
Gen 0 30 colls, 0 par 0.00s 0.00s 0.0001s 0.0003s
Gen 1 4 colls, 0 par 0.03s 0.04s 0.0103s 0.0211s
TASKS: 5 (1 bound, 4 peak workers (4 total), using -N1)
SPARKS: 0 (0 converted, 0 overflowed, 0 dud, 0 GC'd, 0 fizzled)
INIT time 0.00s ( 0.00s elapsed)
MUT time 0.86s (224.38s elapsed)
GC time 0.03s ( 0.05s elapsed)
RP time 0.00s ( 0.00s elapsed)
PROF time 0.00s ( 0.00s elapsed)
EXIT time 0.00s ( 0.00s elapsed)
Total time 0.90s (224.43s elapsed)
Alloc rate 26,778,662 bytes per MUT second
Productivity 96.9% of total user, 0.4% of total elapsed
gc_alloc_block_sync: 0
whitehole_spin: 0
gen[0].sync: 0
gen[1].sync: 0
real 3m44.447s
user 0m0.896s
sys 0m0.320s
和profile:
$ time mysite +RTS -I0
^C 23,024,424 bytes allocated in the heap
19,367,640 bytes copied during GC
2,319,960 bytes maximum residency (94 sample(s))
211,312 bytes maximum slop
6 MB total memory in use (0 MB lost due to fragmentation)
Tot time (elapsed) Avg pause Max pause
Gen 0 27 colls, 0 par 0.00s 0.00s 0.0002s 0.0005s
Gen 1 94 colls, 0 par 1.09s 1.04s 0.0111s 0.0218s
TASKS: 5 (1 bound, 4 peak workers (4 total), using -N1)
SPARKS: 0 (0 converted, 0 overflowed, 0 dud, 0 GC'd, 0 fizzled)
INIT time 0.00s ( 0.00s elapsed)
MUT time 1.00s (201.66s elapsed)
GC time 1.07s ( 1.03s elapsed)
RP time 0.00s ( 0.00s elapsed)
PROF time 0.02s ( 0.02s elapsed)
EXIT time 0.00s ( 0.00s elapsed)
Total time 2.09s (202.68s elapsed)
Alloc rate 23,115,591 bytes per MUT second
Productivity 47.7% of total user, 0.5% of total elapsed
gc_alloc_block_sync: 0
whitehole_spin: 0
gen[0].sync: 0
gen[1].sync: 0
real 3m22.697s
user 0m2.088s
sys 0m0.060s
mysite.prof:
Sun May 31 19:16 2015 Time and Allocation Profiling Report (Final)
mysite +RTS -N -p -s -h -i0.1 -I0 -RTS
total time = 0.05 secs (49 ticks @ 1000 us, 1 processor)
total alloc = 17,590,528 bytes (excludes profiling overheads)
COST CENTRE MODULE %time %alloc
MAIN MAIN 98.0 93.7
acquireSeedSystem.. System.Random.MWC 2.0 0.0
toByteString Data.Serialize.Builder 0.0 3.9
individual inherited
COST CENTRE MODULE no. entries %time %alloc %time %alloc
MAIN MAIN 5684 0 98.0 93.7 100.0 100.0
createSystemRandom System.Random.MWC 11396 0 0.0 0.0 2.0 0.3
withSystemRandom System.Random.MWC 11397 0 0.0 0.1 2.0 0.3
acquireSeedSystem System.Random.MWC 11399 0 0.0 0.0 2.0 0.2
acquireSeedSystem. System.Random.MWC 11401 1 0.0 0.2 2.0 0.2
acquireSeedSystem.. System.Random.MWC 11403 1 2.0 0.0 2.0 0.0
sndS Data.Serialize.Put 11386 21 0.0 0.0 0.0 0.0
put Data.Serialize 11384 21 0.0 0.0 0.0 0.0
unPut Data.Serialize.Put 11383 21 0.0 0.0 0.0 0.0
toByteString Data.Serialize.Builder 11378 21 0.0 3.9 0.0 4.0
flush. Data.Serialize.Builder 11393 21 0.0 0.0 0.0 0.0
withSize Data.Serialize.Builder 11388 0 0.0 0.0 0.0 0.0
withSize. Data.Serialize.Builder 11389 21 0.0 0.0 0.0 0.0
runBuilder Data.Serialize.Builder 11390 21 0.0 0.0 0.0 0.0
runBuilder Data.Serialize.Builder 11382 21 0.0 0.0 0.0 0.0
unstream/resize Data.Text.Internal.Fusion 11372 174 0.0 0.1 0.0 0.1
CAF GHC.IO.Encoding 11322 0 0.0 0.0 0.0 0.0
CAF GHC.IO.FD 11319 0 0.0 0.0 0.0 0.0
CAF GHC.IO.Handle.FD 11318 0 0.0 0.2 0.0 0.2
CAF GHC.Event.Thread 11304 0 0.0 0.0 0.0 0.0
CAF GHC.Conc.Signal 11292 0 0.0 0.0 0.0 0.0
CAF GHC.IO.Encoding.Iconv 11288 0 0.0 0.0 0.0 0.0
CAF GHC.TopHandler 11284 0 0.0 0.0 0.0 0.0
CAF GHC.Event.Control 11271 0 0.0 0.0 0.0 0.0
CAF Main 11263 0 0.0 0.0 0.0 0.0
main Main 11368 1 0.0 0.0 0.0 0.0
CAF Application 11262 0 0.0 0.0 0.0 0.0
CAF Foundation 11261 0 0.0 0.0 0.0 0.0
CAF Model 11260 0 0.0 0.1 0.0 0.3
unstream/resize Data.Text.Internal.Fusion 11375 35 0.0 0.1 0.0 0.1
CAF Settings 11259 0 0.0 0.1 0.0 0.2
unstream/resize Data.Text.Internal.Fusion 11370 20 0.0 0.1 0.0 0.1
CAF Database.Persist.Postgresql 6229 0 0.0 0.3 0.0 0.9
unstream/resize Data.Text.Internal.Fusion 11373 93 0.0 0.6 0.0 0.6
CAF Database.PostgreSQL.Simple.Transaction 6224 0 0.0 0.0 0.0 0.0
CAF Database.PostgreSQL.Simple.TypeInfo.Static 6222 0 0.0 0.0 0.0 0.0
CAF Database.PostgreSQL.Simple.Internal 6219 0 0.0 0.0 0.0 0.0
CAF Yesod.Static 6210 0 0.0 0.0 0.0 0.0
CAF Crypto.Hash.Conduit 6193 0 0.0 0.0 0.0 0.0
CAF Yesod.Default.Config2 6192 0 0.0 0.0 0.0 0.0
unstream/resize Data.Text.Internal.Fusion 11371 1 0.0 0.0 0.0 0.0
CAF Yesod.Core.Internal.Util 6154 0 0.0 0.0 0.0 0.0
CAF Text.Libyaml 6121 0 0.0 0.0 0.0 0.0
CAF Data.Yaml 6120 0 0.0 0.0 0.0 0.0
CAF Data.Yaml.Internal 6119 0 0.0 0.0 0.0 0.0
unstream/resize Data.Text.Internal.Fusion 11369 1 0.0 0.0 0.0 0.0
CAF Database.Persist.Quasi 6055 0 0.0 0.0 0.0 0.0
unstream/resize Data.Text.Internal.Fusion 11376 1 0.0 0.0 0.0 0.0
CAF Database.Persist.Sql.Internal 6046 0 0.0 0.0 0.0 0.0
unstream/resize Data.Text.Internal.Fusion 11377 6 0.0 0.0 0.0 0.0
CAF Data.Pool 6036 0 0.0 0.0 0.0 0.0
CAF Network.HTTP.Client.TLS 6014 0 0.0 0.0 0.0 0.0
CAF System.X509.Unix 6010 0 0.0 0.0 0.0 0.0
CAF Crypto.Hash.MD5 5927 0 0.0 0.0 0.0 0.0
CAF Data.Serialize 5873 0 0.0 0.0 0.0 0.0
put Data.Serialize 11385 1 0.0 0.0 0.0 0.0
CAF Data.Serialize.Put 5872 0 0.0 0.0 0.0 0.0
withSize Data.Serialize.Builder 11387 1 0.0 0.0 0.0 0.0
CAF Data.Serialize.Builder 5870 0 0.0 0.0 0.0 0.0
flush Data.Serialize.Builder 11392 1 0.0 0.0 0.0 0.0
toByteString Data.Serialize.Builder 11391 0 0.0 0.0 0.0 0.0
defaultSize Data.Serialize.Builder 11379 1 0.0 0.0 0.0 0.0
defaultSize.overhead Data.Serialize.Builder 11381 1 0.0 0.0 0.0 0.0
defaultSize.k Data.Serialize.Builder 11380 1 0.0 0.0 0.0 0.0
CAF Crypto.Random.Entropy.Unix 5866 0 0.0 0.0 0.0 0.0
CAF Network.HTTP.Client.Manager 5861 0 0.0 0.0 0.0 0.0
unstream/resize Data.Text.Internal.Fusion 11374 3 0.0 0.0 0.0 0.0
CAF System.Random.MWC 5842 0 0.0 0.0 0.0 0.0
coff System.Random.MWC 11405 1 0.0 0.0 0.0 0.0
ioff System.Random.MWC 11404 1 0.0 0.0 0.0 0.0
acquireSeedSystem System.Random.MWC 11398 1 0.0 0.0 0.0 0.0
acquireSeedSystem.random System.Random.MWC 11402 1 0.0 0.0 0.0 0.0
acquireSeedSystem.nbytes System.Random.MWC 11400 1 0.0 0.0 0.0 0.0
createSystemRandom System.Random.MWC 11394 1 0.0 0.0 0.0 0.0
withSystemRandom System.Random.MWC 11395 1 0.0 0.0 0.0 0.0
CAF Data.Streaming.Network.Internal 5833 0 0.0 0.0 0.0 0.0
CAF Data.Scientific 5728 0 0.0 0.1 0.0 0.1
CAF Data.Text.Array 5722 0 0.0 0.0 0.0 0.0
CAF Data.Text.Internal 5718 0 0.0 0.0 0.0 0.0
您可以在以下存储库中浏览源代码→https://github.com/Zigazou/Ouep
在Yesod bug跟踪器中发现了一个相关的bug。像这样运行我的程序:
myserver +RTS -I0 -RTS Development
与之前的14% (ARM计算机)相比，现在空闲的CPU使用率几乎为零。I0(即I和0)选项关闭周期性垃圾收集，我认为默认为0.3秒。不确定这对应用程序响应性或内存使用的影响，但至少对我来说，这绝对是罪魁祸首。