Re: [Linuxptp-users] logAnnounceInterval Vs announceReceiptTimeout

[Richard C. <ric...@gm...>]

On Tue, Mar 17, 2015 at 04:04:45PM +0000, Chandra Mallela wrote:
> *         My understanding is that logAnnounceInterval (default 1 in every two seconds) is to be set up at the master and announceReceiptTimeout (default 3 messages before the last message reception) to be at the slave. Am I right?

This is defined by the profile.  What profile are you using?
 
> *         I see more of these erros when I increase the packet frequency for Sync and DelayReq (say 512 packets per second). Are there any optimal values for the above for such high packet frequencies?
> 
> *         Message_interval option also seems to play a role in addition to the increased packet frequency. If I reduce the message_interval to a very less value such as -9 (i.,e., increase the message frequency), the errors due to announce message timeouts seem to increase. Is it expected? Are the optimal values for 'logAnnounceInterval & announceReceiptTimeout' helpful in this case?

There is no "Message_interval" option.
 
> Please share your experience with these options.

You are running an extremely short Sync period.  You can expect packet
loss and related problems.  There is no silver bullet to help you here.

If I were going to attempt 512 Syncs per second, then I would:

- use one step (special HW required)
- reduce the DelayReq to something reasonable (like 1 Hz)
- make sure my kernel has SO_SELECT_ERR_QUEUE

HTH,
Richard