Speed up extremely slow MinGW-w64 compilation/linking?

Question

How can I speed up MinGW-w64's extremely slow C++ compilation/linking?

Compiling a trivial "Hello World" program:

#include <iostream>
int main()
{
    std::cout << "hello world" << std::endl;
}

...takes 3 minutes (!) on this otherwise-unloaded Windows 10 box ( i7-6700 , 32GB of RAM, decent SATA SSD):

> ptime.exe g++ main.cpp

ptime 1.0 for Win32, Freeware - http://www.pc-tools.net/
Copyright(C) 2002, Jem Berkes <jberkes@pc-tools.net>

===  g++ main.cpp ===

Execution time: 180.488 s

Process Explorer shows the g++ process tree bottoming out in ld.exe which doesn't use any appreciable CPU or I/O for the duration.

Running the g++ process tree through API Monitor shows there are three unusually long syscalls in ld.exe : two NtCreateFile() s and a NtOpenFile() , each operating on a.exe and taking 60 seconds apiece.

The slowness only happens when using the default a.exe output; g++ -o foo.exe main.cpp takes 2 seconds, tops.

"Well don't use a.exe as an output name then!" isn't really a solution since this behavior causes CMake to take ages doing compiler feature detection.

GCC toolchain versions:

>g++ --version
g++ (x86_64-posix-seh-rev0, Built by MinGW-W64 project) 8.1.0

>ld --version
GNU ld (GNU Binutils) 2.30

Answer 1

Given that I couldn't repro the problem in a clean Windows 10 VM and the dependence on the output filename led me down the path of anti-virus/anti-malware interference.

fltmc instances listed several possible filesystem filter drivers; guess-n-check narrowed it down to two of Carbon Black 's: carbonblackk & ParityDriver .

Using Regedit to disable them via setting Start to 0x4 ("Disabled", 0x2 == Automatic, 0x3 == Manual) in these two registry keys followed by a reboot fixed the slowness:

• HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\carbonblackk
• HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\ParityDriver