Hi Hermant, On Fri, Sep 14, 2018 at 1:53 PM Hemant Chaudhary <hemantdude.chaudhary@xxxxxxxxx> wrote: > > Please don't get confuse with Cygwin(Windows). I am running apache on NonStop(Tandem). Well, isn't the error_log attached to the previous message relevant (be it cygwin or not)? Btw, LogLevel trace6 would help here. > I have put breakpoint at apr_poll() but it is not going there. > > Few Events of writing : > 1) apache writes 779 bytes to tomcat from apr_socket_sendv() function and writev functions returns success. > 2) apache writes 24604 bytes to tomcat from apr_socket_sendv() function but writev function returns -1 with EWOULDBLOCK and it has timeout=0(because set in writev_nonblocking()) > 3) apache again tries to write 32796 to tomcat from apr_socket_sendv() function but writev function returns -1 with EWOULDBLOCK and it has timeout=0(because set in writev_nonblocking()). > 4) apache again tries to write 40988 to tomcat from apr_socket_sendv() function but writev function returns -1 with EWOULDBLOCK and it has timeout=0(because set in writev_nonblocking()). > 5) apache again tries to write 49180 to tomcat from apr_socket_sendv() function but writev function returns -1 with EWOULDBLOCK and it has timeout=0(because set in writev_nonblocking()). OK, all those EWOULDBLOCK make the core output filter to bufferize the "pending" data for the next time it's called. > 6) After this I am getting 4022 error. Here the 64K bufferized limit/threshold is reached (non_file_bytes_in_brigade >= THRESHOLD_MAX_BUFFER in ap_core_output_filter()), so the core output filter can't continue nonblocking anymore and enters send_brigade_blocking(), which does send_brigade_nonblocking() + apr_poll() until the 64K buffer is sent completely. However it seems that on your system the first call to send_brigade_nonblocking() fails (since apr_poll() is never called), possibly a limit on apr_socket_sendv() (i.e. writev() syscall), either more than 64K total bytes or nvec > 4? I think you need to debug/gdb in send_brigade_nonblocking() for this last call and determine where and why send_brigade_nonblocking() => writev_nonblocking() => apr_socket_send() => writev(vec, nvec) fails. Maybe a unit test (a simple standalone main() program) can determine the limits for writev() on your system, so that the right values for THRESHOLD_MAX_BUFFER and MAX_IOVEC_TO_WRITE (in "server/core_filters.c") can be tuned for NonStop(Tandem) ... Hope that helps, Yann. --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscribe@xxxxxxxxxxxxxxxx For additional commands, e-mail: users-help@xxxxxxxxxxxxxxxx
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