On 20/03/23 22:27 +0000, Jonathan Wakely wrote:
On 06/03/23 20:52 +0100, Jannik Glückert wrote:
we were previously only using sendfile for files smaller than 2GB, as
sendfile needs to be called repeatedly for files bigger than that.
some quick numbers, copying a 16GB file, average of 10 repetitions:
old:
real: 13.4s
user: 0.14s
sys : 7.43s
new:
real: 8.90s
user: 0.00s
sys : 3.68s
Additionally, this fixes
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108178
libstdc++-v3/ChangeLog:
* acinclude.m4 (_GLIBCXX_HAVE_LSEEK): define
* config.h.in: Regenerate.
* configure: Regenerate.
* src/filesystem/ops-common.h: enable sendfile for files
>2GB in std::filesystem::copy_file, skip zero-length files
Also, the ChangeLog entry needs to be indented with tabs, name the
changed functions, and should be complete sentences, e.g.
* acinclude.m4 (_GLIBCXX_HAVE_LSEEK): Define.
* config.h.in: Regenerate.
* configure: Regenerate.
* src/filesystem/ops-common.h (copy_file_sendfile): Define new
function for sendfile logic. Loop to support large files. Skip
zero-length files.
(do_copy_file): Use it.
