[PATCH] lib/core/coio_file: Use eio_sendfile_sync instead of a chunk mode
Vladimir Davydov
vdavydov.dev at gmail.com
Fri Apr 12 16:43:23 MSK 2019
On Wed, Apr 10, 2019 at 10:36:24PM +0300, Cyrill Gorcunov wrote:
> eio library provides a portable version of sendfile syscall
> which works a way more efficient than explicit copying file
> by 4K chunks.
>
> Signed-off-by: Cyrill Gorcunov <gorcunov at gmail.com>
> ---
>
> Test app/fio.test.lua which uses this helper passed.
>
> src/lib/core/coio_file.c | 22 +++++++---------------
> 1 file changed, 7 insertions(+), 15 deletions(-)
>
> diff --git a/src/lib/core/coio_file.c b/src/lib/core/coio_file.c
> index c5b2db781..27806d7d5 100644
> --- a/src/lib/core/coio_file.c
> +++ b/src/lib/core/coio_file.c
> @@ -588,22 +588,14 @@ coio_do_copyfile(eio_req *req)
> goto error_dest;
> }
>
> - enum { COPY_FILE_BUF_SIZE = 4096 };
> -
> - char buf[COPY_FILE_BUF_SIZE];
> -
> - while (true) {
> - ssize_t nread = fio_read(source_fd, buf, sizeof(buf));
> - if (nread < 0)
> - goto error_copy;
> -
> - if (nread == 0)
> - break; /* eof */
> -
> - ssize_t nwritten = fio_writen(dest_fd, buf, nread);
> - if (nwritten < 0)
> - goto error_copy;
> + ssize_t nwritten = eio_sendfile_sync(dest_fd, source_fd, 0, st.st_size);
> + if (nwritten != st.st_size) {
> + say_syserror("sendfile, [%s -> %s]",
> + fio_filename(source_fd),
> + fio_filename(dest_fd));
Other coio/fio methods don't log errors so I don't think this one
should, either.
An extract from the sendfile manual page:
} sendfile() will transfer at most 0x7ffff000 (2,147,479,552) bytes,
} returning the number of bytes actually transferred. (This is true on
} both 32-bit and 64-bit systems.)
So I don't think using sendfile is equivalent to read+write...
> + goto error_copy;
> }
> +
> req->result = 0;
> close(source_fd);
> close(dest_fd);
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