Ffilesystem Benchmarks

These were run ~ commit 8424937f using CMAKE_BUILD_TYPE=Release.

• which(): wallclock time is proportional to the number of directories in PATH and which position in PATH the executable happens to be at.
• homedir(): wallclock time is proportional to the number of environment variables.
• expanduser(): wallclock time varies considerably depending if "" or "/" are the leading characters or not. Also calls homedir().
• canonical(): wallclock time depends on if the path is already absolute and is proportional to the number of symlinks in the path, length of the path, and also calls expanduser().

Linux

Intel Xeon workstation

Clang AMD Clang 16.0.3 (CLANG: AOCC_4.2.0-Build#89 2023_12_13)

Cpp: 1000 x canonical(~/..) = /home: 2.651 us
Cpp: 1000 x expanduser(~/..) = /home: 1.201 us
Cpp: 1000 x homedir() = /home/xxx: 0.425 us
Cpp: 1000 x normal(~/..) = .: 0.36 us
Cpp: 1000 x resolve(~/..) = /home: 2.666 us
Cpp: 1000 x which(sh) = /usr/bin/sh: 41.484 us

NVIDIA nvc 24.3.0

Cpp: 1000 x canonical(~/..) = /home: 2.662 us
Cpp: 1000 x expanduser(~/..) = /home: 1.268 us
Cpp: 1000 x homedir() = /home/xxx: 0.422 us
Cpp: 1000 x normal(~/..) = .: 0.365 us
Cpp: 1000 x resolve(~/..) = /home: 2.827 us
Cpp: 1000 x which(sh) = /usr/bin/sh: 13.265 us

GNU GCC 13.2.1

Cpp: 1000 x canonical(~/..) = /home: 2.708 us
Cpp: 1000 x expanduser(~/..) = /home: 1.171 us
Cpp: 1000 x homedir() = /home/xxx: 0.415 us
Cpp: 1000 x normal(~/..) = .: 0.293 us
Cpp: 1000 x resolve(~/..) = /home: 2.746 us
Cpp: 1000 x which(sh) = /usr/bin/sh: 15.868 us

Intel LLVM 20240000 Intel(R) oneAPI DPC++/C++ Compiler 2024.0.0 (2024.0.0.20231017)

Cpp: 1000 x canonical(~/..) = /home: 2.699 us
Cpp: 1000 x expanduser(~/..) = /home: 1.211 us
Cpp: 1000 x homedir() = /home/xxx: 0.427 us
Cpp: 1000 x normal(~/..) = .: 0.363 us
Cpp: 1000 x resolve(~/..) = /home: 2.738 us
Cpp: 1000 x which(sh) = /usr/bin/sh: 34.633 us

Windows

Core i5 laptop

GNU GCC 13.2.0

Cpp: 1000 x canonical(~/..) = C:/Users: 94.2 us
Cpp: 1000 x expanduser(~/..) = C:/Users: 4.6 us
Cpp: 1000 x homedir() = C:/Users/xxx: 2.5 us
Cpp: 1000 x normal(~/..) = .: 0.4 us
Cpp: 1000 x resolve(~/..) = C:/Users: 93.2 us
Cpp: 1000 x which(cmd.exe) = C:/WINDOWS/system32/cmd.exe: 301.2 us

MSVC 193933522

Cpp: 1000 x canonical(~/..) = C:/Users: 37.9 us
Cpp: 1000 x expanduser(~/..) = C:/Users: 4.4 us
Cpp: 1000 x homedir() = C:/Users/xxx: 3.3 us
Cpp: 1000 x normal(~/..) = .: 0.2 us
Cpp: 1000 x resolve(~/..) = C:/Users: 38 us
Cpp: 1000 x which(cmd.exe) = C:/WINDOWS/system32/cmd.exe: 160.7 us

Intel LLVM 20240002 Intel(R) oneAPI DPC++/C++ Compiler 2024.0.2 (2024.0.2.20231213)

Cpp: 1000 x canonical(~/..) = C:/Users: 40.3 us
Cpp: 1000 x expanduser(~/..) = C:/Users: 5.7 us
Cpp: 1000 x homedir() = C:/Users/xxx: 4.7 us
Cpp: 1000 x normal(~/..) = .: 0.2 us
Cpp: 1000 x resolve(~/..) = C:/Users: 40.3 us
Cpp: 1000 x which(cmd.exe) = C:/WINDOWS/system32/cmd.exe: 272.7 us

WSL (Ubuntu 22.04): GNU GCC 11.4.0

Cpp: 1000 x canonical(~/..) = /home: 2.116 us
Cpp: 1000 x expanduser(~/..) = /home: 0.897 us
Cpp: 1000 x homedir() = /home/xxx: 0.304 us
Cpp: 1000 x normal(~/..) = .: 0.212 us
Cpp: 1000 x resolve(~/..) = /home: 2.129 us
Cpp: 1000 x which(sh) = /usr/bin/sh: 3.213 us

Cygwin: GNU GCC 11.4.0

Cpp: 1000 x canonical(~/..) = /home: 105.9 us
Cpp: 1000 x expanduser(~/..) = /home: 4.4 us
Cpp: 1000 x homedir() = /home/xxx: 1.6 us
Cpp: 1000 x normal(~/..) = .: 0.8 us
Cpp: 1000 x resolve(~/..) = /home: 100.3 us
Cpp: 1000 x which(sh) = /usr/bin/sh: 92.2 us