diff options
Diffstat (limited to 'network_io/win32/sendrecv.c')
| -rw-r--r-- | network_io/win32/sendrecv.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/network_io/win32/sendrecv.c b/network_io/win32/sendrecv.c index 21779082d..a841d222d 100644 --- a/network_io/win32/sendrecv.c +++ b/network_io/win32/sendrecv.c @@ -293,6 +293,28 @@ APR_DECLARE(apr_status_t) apr_socket_sendfile(apr_socket_t *sock, bytes_to_send = *len; *len = 0; + /* According to the documentation [1] TF_USE_KERNEL_APC is the most performant option: + * [[[ + * Directs the driver to use kernel asynchronous procedure calls (APCs) + * instead of worker threads to process long TransmitFile requests. + * Long TransmitFile requests are defined as requests that require more + * than a single read from the file or a cache; the request therefore + * depends on the size of the file and the specified length of the send + * packet. + * + * Use of TF_USE_KERNEL_APC can deliver significant performance benefits. + * It is possible (though unlikely), however, that the thread in which + * context TransmitFile is initiated is being used for heavy computations; + * this situation may prevent APCs from launching. + * ]]] + * + * The downside is not applicable for our use case since calling thread + * is not busy and waiting for operation completion. + * + * [1] https://docs.microsoft.com/en-gb/windows/win32/api/mswsock/nf-mswsock-transmitfile + */ + dwFlags |= TF_USE_KERNEL_APC; + /* Handle the goofy case of sending headers/trailers and a zero byte file */ if (!bytes_to_send && hdtr) { if (hdtr->numheaders) { |