tcpdump mailing list archives
Re: [RFC PATCH 0/2]: hw timestamp support
From: "Mcmillan, Scott A" <scott.a.mcmillan () intel com>
Date: Thu, 3 Jun 2010 09:14:26 -0700
Guy, There isn't a way currently to ask a Linux driver what timestamp options it supports. That doesn't mean something couldn't be done, and I think this would be a very nice feature. Rather than add this capability on a per driver basis, I think changes should be pushed to ethtool to do something like this. That, however, isn't an immediate type of fix. What timestamp information would you like to get from the driver and in what format? The hw timestamp capabilities may depend on the protocol, RX/TX, and so on, so I think at a minimum it would need to be a bit field. I can imagine many variations of hw timestamp capabilities, so extensibility is probably important. Would you like to know the current driver timestamp configuration as well as the hw timestamp capabilities of the driver? Is there value in knowing the hw clock resolution? Thanks, Scott -----Original Message----- From: tcpdump-workers-owner () lists tcpdump org [mailto:tcpdump-workers-owner () lists tcpdump org] On Behalf Of Guy Harris Sent: Friday, May 28, 2010 10:28 PM To: tcpdump-workers () lists tcpdump org Subject: Re: [tcpdump-workers] [RFC PATCH 0/2]: hw timestamp support On May 24, 2010, at 7:26 AM, Mcmillan, Scott A wrote:
This patch adds the capability to select the packet timestamp source. It also adds support for the PACKET_TIMESTAMP Linux kernel setting to specify the source of packet timestamps. The corresponding Linux kernel patch is being submitted concurrently.
Is there a way to ask the driver (e.g., an ioctl) which, if any, time stamp options it supports? That would be useful in an pcap API to get that, so that a GUI-based packet analyzer would know whether to offer a choice of packet timestamp types and, if so, which types to offer. - This is the tcpdump-workers list. Visit https://cod.sandelman.ca/ to unsubscribe. - This is the tcpdump-workers list. Visit https://cod.sandelman.ca/ to unsubscribe.
Current thread:
- Re: [RFC PATCH 0/2]: hw timestamp support, (continued)
- Re: [RFC PATCH 0/2]: hw timestamp support Darren Reed (May 25)
- Re: [RFC PATCH 0/2]: hw timestamp support Mcmillan, Scott A (May 26)
- Re: [RFC PATCH 0/2]: hw timestamp support Darren Reed (May 26)
- Re: [RFC PATCH 0/2]: hw timestamp support Mcmillan, Scott A (May 26)
- Re: [RFC PATCH 0/2]: hw timestamp support Aaron Turner (May 26)
- Re: [RFC PATCH 0/2]: hw timestamp support Guy Harris (May 28)
- Re: [RFC PATCH 0/2]: hw timestamp support Mcmillan, Scott A (Jun 01)
- Re: [RFC PATCH 0/2]: hw timestamp support Mcmillan, Scott A (Jun 03)