Re: [PATCH net-next v2 1/3] net/udpgso_bench_tx: options to exercise TX CMSG

On Tue, May 28, 2019 at 3:24 PM Fred Klassen fklassen@appneta.com wrote:

This enhancement adds options that facilitate load testing with additional TX CMSG options, and to optionally print results of various send CMSG operations.

These options are especially useful in isolating situations where error-queue messages are lost when combined with other CMSG operations (e.g. SO_ZEROCOPY).

New options:

-a - count all CMSG messages and match to sent messages
-T - add TX CMSG that requests TX software timestamps
-H - similar to -T except request TX hardware timestamps
-P - call poll() before reading error queue
-v - print detailed results

v2: Enhancements as per Willem de Bruijn willemb@google.com - Updated control and buffer parameters for recvmsg - poll() parameter cleanup - fail on bad audit results - remove TOS options - improved reporting

Signed-off-by: Fred Klassen fklassen@appneta.com

-static void flush_zerocopy(int fd) +static void flush_cmsg(struct cmsghdr *cmsg) {

•   struct msghdr msg = {0};        /* flush */
  

•   switch (cmsg->cmsg_level) {
  

•   case SOL_SOCKET:
  

•           if (cmsg->cmsg_type == SO_TIMESTAMPING) {
  

•                   int i;
  

•                   i = (cfg_tx_ts == SOF_TIMESTAMPING_TX_HARDWARE) ? 2 : 0;
  

•                   struct scm_timestamping *tss;
  

Please don't mix declarations and code.

•                   tss = (struct scm_timestamping *)CMSG_DATA(cmsg);
  

•                   if (tss->ts[i].tv_sec == 0)
  

•                           stat_tx_ts_errors++;
  

•           } else {
  

•                   error(1, 0,
  

•                         "unknown SOL_SOCKET cmsg type=%u level=%u\n",
  

•                         cmsg->cmsg_type, cmsg->cmsg_level);
  

Technically, no need to repeat cmsg_level

•           }
  

•           break;
  

•   case SOL_IP:
  

•   case SOL_IPV6:
  

•           switch (cmsg->cmsg_type) {
  

•           case IP_RECVERR:
  

•           case IPV6_RECVERR:
  

•           {
  

•                   struct sock_extended_err *err;
  

•                   err = (struct sock_extended_err *)CMSG_DATA(cmsg);
  

•                   switch (err->ee_origin) {
  

•                   case SO_EE_ORIGIN_TIMESTAMPING:
  

•                           // Got a TX timestamp from error queue
  

•                           stat_tx_ts++;
  

•                           break;
  

•                   case SO_EE_ORIGIN_ICMP:
  

•                   case SO_EE_ORIGIN_ICMP6:
  

•                           if (cfg_verbose)
  

•                                   fprintf(stderr,
  

•                                           "received ICMP error: type=%u, code=%u\n",
  

•                                           err->ee_type, err->ee_code);
  

•                           break;
  

•                   case SO_EE_ORIGIN_ZEROCOPY:
  

•                   {
  

•                           __u32 lo = err->ee_info;
  

•                           __u32 hi = err->ee_data;
  

•                           if (hi == lo - 1) {
  

•                                   // TX was aborted
  

where does this come from?

•                                   stat_zcopy_errors++;
  

•                                   if (cfg_verbose)
  

•                                           fprintf(stderr,
  

•                                                   "Zerocopy TX aborted: lo=%u hi=%u\n",
  

•                                                   lo, hi);
  

•                           } else if (hi == lo) {
  

technically, no need to special case

•                                   // single ID acknowledged
  

•                                   stat_zcopies++;
  

•                           } else {
  

•                                   // range of IDs acknowledged
  

•                                   stat_zcopies += hi - lo + 1;
  

•                           }
  

•                           break;
  

+static void set_tx_timestamping(int fd) +{

•   int val = SOF_TIMESTAMPING_OPT_CMSG | SOF_TIMESTAMPING_OPT_ID;
  

Could consider adding SOF_TIMESTAMPING_OPT_TSONLY to not have to deal with a data buffer on recv from errqueue.