On Fri, Oct 15, 2021 at 12:01:24AM +0000, [email protected] wrote:
> > > > If this is a "stack" issue, what can I do to reduce the "message rate"
> > > > or "grant duration" if these are related to whatever a "stack" issue
> > > > is?
> > >
> > > I'd be willing to put my money on a driver bug. But for that you'd
> > > need to confirm that the issue reproduces with the default.cfg and not
> > > just with the
> > > G.8275.2 profile. Don't try to run before you can walk.
>
> So I ran tests using a plain 1588 profile and E2E and yes the problem still
> happens. Here is that config:
There's something that just doesn't compute for me.
In those patches, Christian wrote:
/* Currently, only P2P delay measurement is supported. Setting ocmode
* to slave will work independently of actually being master or slave.
* For E2E delay measurement, switching between master and slave would
* be required, as the KSZ devices filters out PTP messages depending on
* the ocmode setting:
* - in slave mode, DelayReq messages are filtered out
* - in master mode, Sync messages are filtered out
* Currently (and probably also in future) there is no interface in the
* kernel which allows switching between master and slave mode. For
* this reason, E2E cannot be supported. See patchwork for full
* discussion:
*
https://patchwork.ozlabs.org/project/netdev/patch/[email protected]/
*/
ksz9477_ptp_tcmode_set(dev, KSZ9477_PTP_TCMODE_P2P);
ksz9477_ptp_ocmode_set(dev, KSZ9477_PTP_OCMODE_SLAVE);
Did you modify the driver's OCMODE? I am super confused as to which
packets ptp4l is actually waiting for a TX timestamp for. Because if
you're using E2E and not P2P, then the entire ksz9477_port_deferred_xmit()
is just dead code, is it not?
> [global]
> #
> # Default Data Set
(summary of your changes)
twoStepFlag: 1 to 0
slaveOnly: 0 to 1
clockClass: 248 to 6
fault_reset_interval: 4 to -128
tx_timestamp_timeout: 10 to 1000
unicast_listen: 0 to 1
unicast_req_duration: 3600 to 300
summary_interval: 0 to 4
time_stamping: hardware to p2p1step
tsproc_mode: filter to raw_weight
Can you just print the packet in ptp4l? You're using the default.cfg
settings otherwise, so the UDPv4 network_transport, so:
static int udp_send(struct transport *t, struct fdarray *fda,
enum transport_event event, int peer, void *buf, int len,
struct address *addr, struct hw_timestamp *hwts)
...
cnt = sendto(fd, buf, len, 0, &addr->sa, sizeof(addr->sin));
if (cnt < 1) {
pr_err("sendto failed: %m");
return -errno;
}
/*
* Get the time stamp right away.
*/
return event == TRANS_EVENT ? sk_receive(fd, junk, len, NULL, hwts,
MSG_ERRQUEUE) : cnt;
^
you can print the buf here if
sk_receive returns negative
The only place I find where this makes sense to be called from is:
port_delay_request:
if (port_prepare_and_send(p, msg, TRANS_EVENT)) {
But that further suggests that you've modified the driver, because:
/* Defer transmit if waiting for egress time stamp is required. */
static struct sk_buff *ksz9477_defer_xmit(struct dsa_port *dp,
struct sk_buff *skb)
{
/* Use cached PTP msg type from ksz9477_ptp_port_txtstamp(). */
ptp_msg_type = KSZ9477_SKB_CB(clone)->ptp_msg_type;
if (ptp_msg_type != PTP_MSGTYPE_PDELAY_REQ)
goto out_free_clone; /* only PDelay_Req is deferred */
So could you share the exact list of changes you've made to the patches
from the form that they were posted in?
>
> And I did find a bug in the DSA driver but it didn't appear to change
> anything.
>
> In ksz9477_ptp_txtstamp_skb function the "ret" that is being assigned
> by "wait_for_completion_timeout" returning is declared as an "int"
> instead of an "unsigned long" so I fixed that.
Doesn't really make a difference on a 64-bit machine.
Nonetheless, is that the sticking point? Do you see this error message
in dmesg when user space loses the TX timestamp?
dev_err(dev->dev, "timeout waiting for time stamp\n");
> ... still looking for other stuff but again, I'm probably not
> experienced enough (yet) with DSA and LinuxPTP to do much good.
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