tcpdump mailing list archives
Re: Hardware Timestamping Problem
From: Guenter Ebermann <guenter.ebermann () googlemail com>
Date: Thu, 9 Jun 2016 22:19:34 +0200
Am 09.06.2016 um 15:47 schrieb Michael Richardson <mcr () sandelman ca>: Guenter Ebermann <guenter.ebermann () googlemail com> wrote:Hardware timestamping of sending/receiving buffer descriptors is done by NIC.Receiving I understand. Are you sure that the hardware is going to timestamp sent packets, and then turn around and send the back to the kernel?
Yes, the driver must monitor tx descriptor consumption by hardware anyways. E.g. Freescale enhanced three speed ethernet controller (eTSEC) can timestamp send buffers - it writes the timestamps to the beginning of the buffer descriptor. You use such a controller feature to implement PTP (IEEE 1588). For Linux drivers supporting hardware timestamping see [1], chapter 5.3.2. The i350-T4, handled by Linux driver igb, is also supported (igb_ptp.c). It seems it does also timestamp tx buffers. [1] http://linuxptp.sourceforge.net/ _______________________________________________ tcpdump-workers mailing list tcpdump-workers () lists tcpdump org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers
Current thread:
- Re: Hardware Timestamping Problem, (continued)
- Message not available
- Re: Hardware Timestamping Problem Michael Richardson (Jun 08)
- Re: Hardware Timestamping Problem Christian Rupp (Jun 08)
- Re: Hardware Timestamping Problem Christian Rupp (Jun 08)
- Re: Hardware Timestamping Problem Guy Harris (Jun 08)
- Re: Hardware Timestamping Problem Christian (Jun 09)
- Re: Hardware Timestamping Problem Michael Richardson (Jun 08)
- Re: Hardware Timestamping Problem Guenter Ebermann (Jun 08)
- Re: Hardware Timestamping Problem Michael Richardson (Jun 09)
- Re: Hardware Timestamping Problem Christian (Jun 09)
- Re: Hardware Timestamping Problem Guenter Ebermann (Jun 09)
- Re: Hardware Timestamping Problem Guy Harris (Jun 09)
- Re: Hardware Timestamping Problem Guenter Ebermann (Jun 09)
- Re: Hardware Timestamping Problem Guy Harris (Jun 09)
- Re: Hardware Timestamping Problem Guenter Ebermann (Jun 09)
- Re: Hardware Timestamping Problem Guy Harris (Jun 09)