Bug #80061 [PATCH]: Copying large files may have suboptimal performance

Edit report at https://bugs.php.net/bug.php?id=80061&edit=1 ID: 80061 Patch added by: cmb@php.net Reported by: cmb@php.net Summary: Copying large files may have suboptimal performance Status: Assigned Type: Bug Package: Performance problem Operating System: * PHP Version: 7.4Git-2020-09-04 (Git) Assigned To: cmb Block user comment: N Private report: N New Comment: The following pull request has been associated: Patch Name: Fix mmap copying On GitHub: https://github.com/php/php-src/pull/6078 Patch: https://github.com/php/php-src/pull/6078.patch Previous Comments: ------------------------------------------------------------------------ [2020-09-04 16:29:42] cmb@php.net Description: ------------ As of PHP 7.4.0, large files are supposed to be copied by mapping them into virtual memory at once. That obviously can't work for files which are larger than any possibly free memory segment. So copying files of 1 GiB or 2 GiB is not unlikely to fail for x86 architectures, for instance. If the memory mapping fails, we fall back to reading and writing in small chunks, which has suboptimal performance. See also <https://github.com/php/php-src/pull/5319#issuecomment-605901029>. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=80061&edit=1