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

[Fred Klassen]

> On May 28, 2019, at 2:35 PM, Willem de Bruijn <willemdebruijn.kernel@xxxxxxxxx> 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.