From: Stephen Hemminger <stephen@networkplumber.org>
To: Dawid Wesierski <dawid.wesierski@intel.com>
Cc: dev@dpdk.org, bruce.richardson@intel.com,
anatoly.burakov@intel.com, vladimir.medvedkin@intel.com,
reshma.pattan@intel.com, thomas@monjalon.net,
andrew.rybchenko@oktetlabs.ru, marek.kasiewicz@intel.com
Subject: Re: [PATCH 6/7] pcapng: add user-supplied timestamp support
Date: Thu, 30 Apr 2026 07:09:32 -0700 [thread overview]
Message-ID: <20260430070932.16d20726@phoenix.local> (raw)
In-Reply-To: <20260429073111.3712950-7-dawid.wesierski@intel.com>
On Wed, 29 Apr 2026 03:31:10 -0400
Dawid Wesierski <dawid.wesierski@intel.com> wrote:
> From: Marek Kasiewicz <marek.kasiewicz@intel.com>
>
> Add rte_pcapng_copy_ts() which accepts an optional timestamp parameter
> in nanoseconds. When the timestamp is non-zero, it is used directly
> instead of reading the TSC. This allows applications to provide
> hardware PTP timestamps from the NIC, enabling accurate packet capture
> with PTP-domain timing rather than host-local TSC values.
Also, the HW timestamp would have to be in ns since Unix Epoch
not what HW clock is. That is a hard thing to do...
I would rather have the pcapng infrastructure know how to use
hardware timestamp dynamic field if present. But the problem is
getting the conversion right; it would have to compute offset and
resolution per NIC, and NIC's roll over too fast. The problem is
hard.
Bottom line: needs lots more work
prev parent reply other threads:[~2026-04-30 14:09 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260429073111.3712950-1-dawid.wesierski@intel.com>
[not found] ` <20260429073111.3712950-7-dawid.wesierski@intel.com>
2026-04-30 14:05 ` [PATCH 6/7] pcapng: add user-supplied timestamp support Stephen Hemminger
2026-04-30 14:06 ` Stephen Hemminger
2026-04-30 14:09 ` Stephen Hemminger [this message]
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