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fix performance of #7714 by forcing use of Zip2{Any,Any}
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discovered using TRACE_INFERENCE. this was specializing Zip2 for
all method signatures processed by the reflective code.
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@JeffBezanson
JeffBezanson committed Dec 7, 2014
1 parent d86d001 commit 052f54e
Showing 1 changed file with 1 addition and 1 deletion.
2 changes: 1 addition & 1 deletion base/replutil.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -155,7 +155,7 @@ function showerror(io::IO, e::MethodError)
print(buf, " $(e.f.env.name)(")
first = true
right_matches = 0
for (arg, sigtype) in zip(e.args, method.sig)
for (arg, sigtype) in Zip2{Any,Any}(e.args, method.sig)
if first
first = false
else
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2 comments on commit 052f54e

@ivarne
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@ivarne ivarne commented on 052f54e Dec 8, 2014

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Cool fix!

Any lessons we can learn from this and put into the "Performance tips" section of the manual?

@JeffBezanson
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I guess the general lesson is that reflective code can wreak havoc with julia's specialization mechanism. Specialization depends on the sparseness of interactions between types, but when you have code whose explicit purpose is to iterate over everything in the system that assumption is violated.

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