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From: bugzilla@dpdk.org
To: dev@dpdk.org
Subject: [DPDK/ethdev Bug 1840] net/pcap: missing read_clock operation
Date: Fri, 28 Nov 2025 18:29:39 +0000	[thread overview]
Message-ID: <bug-1840-3@http.bugs.dpdk.org/> (raw)

http://bugs.dpdk.org/show_bug.cgi?id=1840

            Bug ID: 1840
           Summary: net/pcap: missing read_clock operation
           Product: DPDK
           Version: 25.07
          Hardware: All
                OS: All
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: ethdev
          Assignee: dev@dpdk.org
          Reporter: stephen@networkplumber.org
  Target Milestone: ---

The pcap PMD provides receive timestamps from the pcap interface into the mbuf.
But there are a couple of issues with it.

The units of the timestamp are limited to microseconds now, but the pcap
library has a flag to provide nanosecond resolution. This should be used. One
caveat is that the API is misleading in reporting timestamp. The packet header
struct gives timestamp as a timeval (ie. usec) but if nanosecond mode flag is
used then the timestamp is really in timespec (ie nanoseconds).

The pcap PMD doesn't have a read_clock device operation so the application can
not determine the units of the receive timestamp. Pcap should behave like a
hardware PMD and return the underlying clock value.

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                 reply	other threads:[~2025-11-28 18:29 UTC|newest]

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