Re: FYI, 2.73 slower than 2.72

On 2026-03-18 09:57, Zack Weinberg wrote:

> I'm currently looking into the possibility that the
> 'copy_file_range' system call is inefficient for small files

An interesting hypothesis. But on my platform (Fedora 43), for small 
files the 'cat' bottleneck is the mmap/munmap/mprotect/etc. syscalls for 
startup. copy_file_range takes only 10% of the CPU time.


> Do you happen to remember why we concatenate confdefs.h and the test
> program, instead of #include-ing confdefs.h from the test program?

Sorry, no.