<p dir="ltr">I think there's a problem with the number of cores that they report: the vms/containers report 16 cores, while they only have 2. Perhaps -j2 would work better?</p>
<br><div class="gmail_quote"><div dir="ltr">Wojtek Narczyński <<a href="mailto:wojtek@power.com.pl">wojtek@power.com.pl</a>> schrieb am So., 28. Feb. 2016 18:22:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On 22.02.2016 22:27, Johannes Waldmann wrote:<br>
>> I presume you are using the -j switch.<br>
> Does it really help? I recently found that for travis builds,<br>
> it is used by default (first surprise)<br>
> but it's faster when it's turned off (second surprise).<br>
><br>
> <a href="https://ghc.haskell.org/trac/ghc/ticket/10818#comment:15" rel="noreferrer" target="_blank">https://ghc.haskell.org/trac/ghc/ticket/10818#comment:15</a><br>
><br>
><br>
<br>
I meant ghc -j, not cabal -j. It does work very well.<br>
<br>
I did the following test.<br>
<br>
wojtek@Desktop2016:~/src/tpdb-1.2.0/src$ time ghc -j -fforce-recomp<br>
TPDB/*.hs TPDB/XTC/*.hs TPDB/DP/*.hs TPDB/CPF/Proof/*.hs TPDB/Data/*.hs<br>
TPDB/Plain/*.hs TPDB/Xml/*.hs<br>
[24 of 24] Compiling TPDB.Mirror      ( TPDB/Mirror.hs, TPDB/Mirror.o )<br>
real    0m1.221s<br>
user    0m2.416s<br>
sys    0m0.604s<br>
<br>
wojtek@Desktop2016:~/src/tpdb-1.2.0/src$ time ghc -fforce-recomp<br>
TPDB/*.hs TPDB/XTC/*.hs TPDB/DP/*.hs TPDB/CPF/Proof/*.hs TPDB/Data/*.hs<br>
TPDB/Plain/*.hs TPDB/Xml/*.hs<br>
[24 of 24] Compiling TPDB.Mirror      ( TPDB/Mirror.hs, TPDB/Mirror.o )<br>
real    0m1.791s<br>
user    0m1.660s<br>
sys    0m0.060s<br>
<br>
wojtek@Desktop2016:~/src/tpdb-1.2.0$ time cabal build -j<br>
[24 of 24] Compiling TPDB.CPF.Proof.Util ( src/TPDB/CPF/Proof/Util.hs,<br>
dist/build/TPDB/CPF/Proof/Util.o )<br>
real    0m5.544s<br>
user    0m10.912s<br>
sys    0m2.628s<br>
<br>
Something is indeed wrong, either cabal is misusing ghc, or you are<br>
misusing cabal.<br>
<br>
This package is not a good test case for parallel build, it is too small.<br>
<br>
--<br>
Wojtek<br>
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</blockquote></div>