Re: [PATCH v2 1/2] libstdc++: also use sendfile for big files

[Jonathan Wakely <jwakely@redhat.com>]

[-- Attachment #1: Type: text/plain, Size: 1811 bytes --]

On Wed, 22 Mar 2023 at 12:14, Jonathan Wakely <jwakely@redhat.com> wrote:

>
>
> On Mon, 20 Mar 2023 at 22:30, Jonathan Wakely via Libstdc++ <
> libstdc++@gcc.gnu.org> wrote:
>
>> 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.
>>
>>
> Here's what I plan to commit in a few weeks when GCC 14 Stage 1 opens.
>
>
>
Pushed to trunk now (after testing on btrfs, xfs, and tmpfs using kernel
6.3 and on xfs using kernel 3.10).