macro threadcall does not accept `Ref` arguments #30864

felipenoris · 2019-01-28T04:14:38Z

While working on a driver for Oracle, I experimented with macro threadcall on this function.

# int dpiConn_create(const dpiContext *context, const char *userName, uint32_t userNameLength, const char *password, uint32_t passwordLength, const char *connectString, uint32_t connectStringLength, dpiCommonCreateParams *commonParams, dpiConnCreateParams *createParams, dpiConn **conn)
function dpiConn_create(context_handle::Ptr{Cvoid}, user::String, password::String, connect_string::String, common_params_ref::Ref{OraCommonCreateParams}, conn_create_params_ref::Ref{OraConnCreateParams}, dpi_conn_handle_ref::Ref{Ptr{Cvoid}})
    userNameLength = sizeof(user)
    passwordLength = sizeof(password)
    connectStringLength = sizeof(connect_string)

    @threadcall((:dpiConn_create, libdpi), OraResult, (Ptr{Cvoid}, Ptr{UInt8}, UInt32, Ptr{UInt8}, UInt32, Ptr{UInt8}, UInt32, Ref{OraCommonCreateParams}, Ref{OraConnCreateParams}, Ref{Ptr{Cvoid}}), context_handle, user, userNameLength, password, passwordLength, connect_string, connectStringLength, common_params_ref, conn_create_params_ref, dpi_conn_handle_ref)
end

All Ref arguments are outputs of the C API.

When I run this function, I get an error:

ERROR: LoadError: argument is an abstract type; size is indeterminate. 
Stacktrace:
 [1] _mapreduce at ./reduce.jl:316 [inlined]
 [2] _mapreduce_dim at ./reducedim.jl:308 [inlined]
 [3] #mapreduce#548 at ./reducedim.jl:304 [inlined]
 [4] mapreduce at ./reducedim.jl:304 [inlined]
 [5] _sum at ./reducedim.jl:653 [inlined]
 [6] #sum#551 at ./reducedim.jl:649 [inlined]
 [7] sum at ./reducedim.jl:649 [inlined]
 [8] do_threadcall(::Ptr{Nothing}, ::Type, ::Array{Any,1}, ::Array{Any,1}) at ./threadcall.jl:67
 [9] dpiConn_create(::Ptr{Nothing}, ::String, ::String, ::String, ::Base.RefValue{Oracle.OraCommonCreateParams}, ::Base.RefValue{Oracle.OraConnCreateParams}, ::Base.RefValue{Ptr{Nothing}}) at ./threadcall.jl:52
 [10] Oracle.Connection(::Oracle.Context, ::String, ::String, ::String, ::Oracle.CommonCreateParams, ::Oracle.ConnCreateParams) at /home/felipenoris/Documents/src/Oracle.jl/src/connection.jl:60
 [11] main() at /home/felipenoris/Documents/src/Oracle.jl/src/connection.jl:76
 [12] top-level scope at /home/felipenoris/Documents/src/Oracle.jl/benchmarks/thread.jl:38
 [13] include at ./boot.jl:326 [inlined]
 [14] include_relative(::Module, ::String) at ./loading.jl:1041
 [15] include(::Module, ::String) at ./Base.jl:29
 [16] include(::String) at ./client.jl:418
 [17] top-level scope at REPL[3]:1
in expression starting at /home/felipenoris/Documents/src/Oracle.jl/benchmarks/thread.jl:38

After digging into the code, I found that the problem is the Ref type:

julia> sizeof(Ref{Ptr{Cvoid}})
ERROR: argument is an abstract type; size is indeterminate
Stacktrace:
 [1] sizeof(::Type) at ./essentials.jl:416
 [2] top-level scope at none:0

julia> sizeof(Ref{UInt8})
ERROR: argument is an abstract type; size is indeterminate
Stacktrace:
 [1] sizeof(::Type) at ./essentials.jl:416
 [2] top-level scope at none:0

The text was updated successfully, but these errors were encountered:

martinholters · 2019-01-28T07:56:09Z

Base.RefValue?

felipenoris · 2019-01-28T11:53:12Z

I didn't know Base.RefValue existed. But if I change the implementation to use it, I get another error:

ArgumentError: threadcall requires isbits argument types

~~Which is strange, because a regular pointer Ptr{Cvoid} is not a bits type also.~~

I would argue that @threadcall should have the same requirements as the ccall function.

amcostant · 2019-07-17T19:56:05Z

I am having a similar problem with my code.

function pdiff(b1::Array{Basic,1}, b2::Basic)
    dfdx = Array{Basic}(undef,length(b1))
    Threads.@threads for i = 1:length(b1)
        a = Basic()
        ret = @threadcall((:basic_diff, libsymengine), Int, (Ref{Basic}, Ref{Basic}, Ref{Basic}), a, b1[i], b2)
        dfdx[i] = a
    end
    return dfdx
end

I get the following error


julia> pdiff(ex,a)

Error thrown in threaded loop on thread 16: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 5: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 9: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 2: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 13: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 12: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 8: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 6: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 15: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 1: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 0: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 19: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 20: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 10: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 14: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 3: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 7: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 18: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 21: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 17: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 11: ErrorException("argument is an abstract type; size is indeterminate")
Error thrown in threaded loop on thread 4: ErrorException("argument is an abstract type; size is indeterminate")10000-element Array{Basic,1}:
 #undef
 #undef
 #undef
   ⋮   
 #undef
 #undef
 #undef

julia>

StefanKarpinski · 2019-07-17T20:30:38Z

@threadcall was always a stopgap until we could actually run Julia code on multiple threads, which we can now do. In 1.3, full threading functionality will no longer be experimental, and @threadcall will be completely vestigial. To that end it's probably not worth fixing it, but perhaps it can be reimplemented in terms of the new proper threading functionality.

amcostant · 2019-07-17T21:19:39Z

@StefanKarpinski How would you recommend I implement the above code in V1.3? Thanks!

StefanKarpinski · 2019-07-18T15:48:55Z

Once some version of #32600 is merged, you would use that macro. I would rewrite your code to show this but I'm a little confused about why you're using both @threads and @threadcall. Can you explain what your code is trying to do?

amcostant · 2019-07-18T18:51:36Z

I think I misunderstood how @threadcall works.
I got the code to work like this and ran it

function pdiff(b1::Array{Basic,1}, b2::Basic)
    dfdx = Array{Basic}(undef,length(b1))
    Threads.@threads for i = 1:length(b1)
        a = Basic()
        ret = ccall((:basic_diff, libsymengine), Int, (Ref{Basic}, Ref{Basic}, Ref{Basic}), a, b1[i], b2)
        dfdx[i] = a
    end
    return dfdx
end

and on my laptop I saw a O(n^1/2) improvment with number of threads, but on my desktop I saw a decrease in performance with adding cores.
this might be helpful
desktop:

julia> versioninfo()
Julia Version 1.1.1
Commit 55e36cc308 (2019-05-16 04:10 UTC)
Platform Info:
  OS: Linux (x86_64-pc-linux-gnu)
  CPU: Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-6.0.1 (ORCJIT, haswell)
Environment:
  JULIA_NUM_THREADS = 44

My laptop has the same Julia version and runs on windows.
Any help would be greatly appreciated.

StefanKarpinski · 2019-07-18T21:53:21Z

Help with performance is more appropriate for discourse.

felipenoris · 2019-07-19T13:33:37Z

Closing, as I understand the new thread api will replace threadcall.

felipenoris · 2020-04-24T22:40:48Z

@threadcall was always a stopgap until we could actually run Julia code on multiple threads, which we can now do. In 1.3, full threading functionality will no longer be experimental, and @threadcall will be completely vestigial. To that end it's probably not worth fixing it, but perhaps it can be reimplemented in terms of the new proper threading functionality.

@StefanKarpinski , sorry about bringing this up again, I just would like to make a quick check on this, given that 1.4 is out and the Threading funcionality is more mature. Is it still true that threadcall is an "old" thing and we should use replace it with the new Threading API? What makes me think about using threadcall is that there's no setup for the user since Julia starts with 4 libuv threads (based on the docs), but 1 julia thread unless the user specifies a JULIA_NUM_THREADS.

amcostant mentioned this issue Jul 17, 2019

Parallelization on CPU segfaults on occasion symengine/SymEngine.jl#166

Closed

felipenoris closed this as completed Jul 19, 2019

ssfrr mentioned this issue Nov 20, 2019

non-blocking read/write JuliaAudio/LibSndFile.jl#15

Open

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macro threadcall does not accept `Ref` arguments #30864

macro threadcall does not accept `Ref` arguments #30864

felipenoris commented Jan 28, 2019 •

edited

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martinholters commented Jan 28, 2019

felipenoris commented Jan 28, 2019 •

edited

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amcostant commented Jul 17, 2019 •

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StefanKarpinski commented Jul 17, 2019

amcostant commented Jul 17, 2019

StefanKarpinski commented Jul 18, 2019

amcostant commented Jul 18, 2019

StefanKarpinski commented Jul 18, 2019

felipenoris commented Jul 19, 2019

felipenoris commented Apr 24, 2020

macro threadcall does not accept Ref arguments #30864

macro threadcall does not accept Ref arguments #30864

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felipenoris commented Jan 28, 2019 • edited Loading

martinholters commented Jan 28, 2019

felipenoris commented Jan 28, 2019 • edited Loading

amcostant commented Jul 17, 2019 • edited Loading

StefanKarpinski commented Jul 17, 2019

amcostant commented Jul 17, 2019

StefanKarpinski commented Jul 18, 2019

amcostant commented Jul 18, 2019

StefanKarpinski commented Jul 18, 2019

felipenoris commented Jul 19, 2019

felipenoris commented Apr 24, 2020

macro threadcall does not accept `Ref` arguments #30864

macro threadcall does not accept `Ref` arguments #30864

felipenoris commented Jan 28, 2019 •

edited

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felipenoris commented Jan 28, 2019 •

edited

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amcostant commented Jul 17, 2019 •

edited

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