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

On May 28, 2019, at 2:35 PM, Willem de Bruijn willemdebruijn.kernel@gmail.com wrote:

...

-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

Fixing this as well as other declarations for v3.

...

•                   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

Will fix all 3 similar messages

...

•           }
  

•           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?

This check can be removed. In sock_zerocopy_callback() this check was intended to cover the condition where len == 0, however it appears that it is impossible.

/* if !len, there was only 1 call, and it was aborted * so do not queue a completion notification */

if (!uarg->len || sock_flag(sk, SOCK_DEAD)) goto release;

len = uarg->len; lo = uarg->id; hi = uarg->id + len - 1;

...

•                                   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

Removed

...

•                                   // 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.

Will add and modify code appropriately for v3.