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From: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: dev@dpdk.org, Tyler Retzlaff <roretzla@microsoft.com>,
	Mike Wells <mike.wells@telchemy.com>,
	Narcisa Ana Maria Vasile <navasile@linux.microsoft.com>,
	Dmitry Malloy <dmitrym@microsoft.com>,
	Pallavi Kadam <pallavi.kadam@intel.com>,
	Ray Kinsella <mdr@ashroe.eu>, Neil Horman <nhorman@tuxdriver.com>
Subject: Re: [dpdk-dev] [PATCH v2 1/6] eal: add internal API for current time
Date: Tue, 16 Mar 2021 23:07:42 +0300	[thread overview]
Message-ID: <20210316230742.4720f42d@sovereign> (raw)
In-Reply-To: <20210316115933.06d1f9de@hermes.local>

2021-03-16 11:59 (UTC-0700), Stephen Hemminger:
> On Sun, 14 Feb 2021 05:16:11 +0300
> Dmitry Kozlyuk <dmitry.kozliuk@gmail.com> wrote:
> 
> > +rte_time_get_us(struct rte_time_us *now)
> > +{
> > +	struct timeval sys;
> > +
> > +	gettimeofday(&sys, NULL);
> > +	now->sec = sys.tv_sec;
> > +	now->usec = sys.tv_usec;
> > +}  
> 
> Why would drivers want the default (wall clock) time instead
> of using monotonic clock. The wall clock gets changed by NTP
> and that is rarely what you want except for the case of log messages.

* gettimeofday() is mostly used to measure time (tests, hns3 PMD), so you're
right, monotonic clock is what that code really needs.

* ena PMD uses gettimeofday() with pthread_cond_timedwait() without calling
pthread_cond_setclock(), which is a bug, I believe.

* hns3 PMD actually uses gettimeofday() for logs.

For wall clock time there is C11 timespec_get(), so I agree this API should
be changed to monotonic, thanks.

  reply	other threads:[~2021-03-16 20:07 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-14  1:20 [dpdk-dev] [PATCH 0/6] net/pcap: build on Windows Dmitry Kozlyuk
2021-02-14  1:20 ` [dpdk-dev] [PATCH 1/6] eal: add internal API for current time Dmitry Kozlyuk
2021-03-01 22:31   ` Nick Connolly
2021-03-01 22:36     ` Nick Connolly
2021-02-14  1:20 ` [dpdk-dev] [PATCH 2/6] net/pcap: fix format string Dmitry Kozlyuk
2021-03-01 22:33   ` Nick Connolly
2021-02-14  1:20 ` [dpdk-dev] [PATCH 3/6] net/pcap: move OS-dependent code to separate files Dmitry Kozlyuk
2021-02-14  1:20 ` [dpdk-dev] [PATCH 4/6] net/pcap: add libpcap wrappers Dmitry Kozlyuk
2021-02-14  1:20 ` [dpdk-dev] [PATCH 5/6] config: discover libpcap on Windows Dmitry Kozlyuk
2021-02-14  1:20 ` [dpdk-dev] [PATCH 6/6] net/pcap: build " Dmitry Kozlyuk
2021-02-14  2:16 ` [dpdk-dev] [PATCH v2 0/6] " Dmitry Kozlyuk
2021-02-14  2:16   ` [dpdk-dev] [PATCH v2 1/6] eal: add internal API for current time Dmitry Kozlyuk
2021-03-01 22:39     ` Nick Connolly
2021-03-05 17:50     ` Jie Zhou
2021-03-16  9:18     ` Thomas Monjalon
2021-03-16 18:59     ` Stephen Hemminger
2021-03-16 20:07       ` Dmitry Kozlyuk [this message]
2021-03-17  9:50         ` Morten Brørup
2021-02-14  2:16   ` [dpdk-dev] [PATCH v2 2/6] net/pcap: fix format string Dmitry Kozlyuk
2021-02-25 14:45     ` Ferruh Yigit
2021-03-02 11:48       ` [dpdk-dev] [dpdk-stable] " Ferruh Yigit
2021-02-14  2:16   ` [dpdk-dev] [PATCH v2 3/6] net/pcap: move OS-dependent code to separate files Dmitry Kozlyuk
2021-02-25 14:51     ` Ferruh Yigit
2021-02-25 16:05       ` Dmitry Kozlyuk
2021-02-14  2:16   ` [dpdk-dev] [PATCH v2 4/6] net/pcap: add libpcap wrappers Dmitry Kozlyuk
2021-02-25 14:59     ` Ferruh Yigit
2021-02-25 19:04       ` Dmitry Kozlyuk
2021-02-25 20:31         ` Nick Connolly
2021-02-25 23:10           ` Dmitry Kozlyuk
2021-03-01 21:43             ` Nick Connolly
2021-03-01 23:05               ` Dmitry Kozlyuk
2021-03-01 23:23                 ` Dmitry Kozlyuk
2021-03-02 11:22                 ` Nick Connolly
2021-03-03 16:32                   ` Dmitry Kozlyuk
2021-03-03 16:47                     ` Ferruh Yigit
2021-03-03 18:19                       ` Dmitry Kozlyuk
2021-03-03 19:30                         ` Ferruh Yigit
2021-03-03 23:03                           ` Dmitry Kozlyuk
2021-02-14  2:16   ` [dpdk-dev] [PATCH v2 5/6] config: discover libpcap on Windows Dmitry Kozlyuk
2021-02-25 15:02     ` Ferruh Yigit
2021-02-25 16:04       ` Dmitry Kozlyuk
2021-02-25 16:33         ` Bruce Richardson
2021-02-25 17:42           ` Dmitry Kozlyuk
2021-03-16  9:16             ` Thomas Monjalon
2021-03-16  9:37               ` Dmitry Kozlyuk
2021-02-14  2:16   ` [dpdk-dev] [PATCH v2 6/6] net/pcap: build " Dmitry Kozlyuk
2021-03-24  0:50   ` [dpdk-dev] [PATCH v3 0/3] " Dmitry Kozlyuk
2021-03-24  0:50     ` [dpdk-dev] [PATCH v3 1/3] eal/windows: add timespec_get shim for MinGW Dmitry Kozlyuk
2021-03-24  0:50     ` [dpdk-dev] [PATCH v3 2/3] net/pcap: move OS-dependent code to separate files Dmitry Kozlyuk
2021-03-24  0:50     ` [dpdk-dev] [PATCH v3 3/3] net/pcap: build on Windows Dmitry Kozlyuk
2021-04-09 10:51     ` [dpdk-dev] [PATCH v3 0/3] " Ferruh Yigit
2021-04-09 11:03       ` Dmitry Kozlyuk
2021-04-09 11:24         ` Ferruh Yigit
2021-04-15 22:10     ` [dpdk-dev] [PATCH v4 " Dmitry Kozlyuk
2021-04-15 22:10       ` [dpdk-dev] [PATCH v4 1/3] eal/windows: add timespec_get shim for MinGW Dmitry Kozlyuk
2021-04-15 22:10       ` [dpdk-dev] [PATCH v4 2/3] net/pcap: move OS-dependent code to separate files Dmitry Kozlyuk
2021-04-15 22:10       ` [dpdk-dev] [PATCH v4 3/3] net/pcap: build on Windows Dmitry Kozlyuk
2021-04-19 21:05         ` Tyler Retzlaff
2021-04-16 17:22       ` [dpdk-dev] [PATCH v4 0/3] " Ferruh Yigit
2021-04-20 22:20       ` Thomas Monjalon
2021-04-21 14:53         ` Dmitry Kozlyuk
2021-04-21 18:12           ` Thomas Monjalon
2021-04-21 19:33       ` [dpdk-dev] [PATCH v5 " Dmitry Kozlyuk
2021-04-21 19:33         ` [dpdk-dev] [PATCH v5 1/3] eal: add timespec_get shim Dmitry Kozlyuk
2021-04-21 19:33         ` [dpdk-dev] [PATCH v5 2/3] net/pcap: move OS-dependent code to separate files Dmitry Kozlyuk
2021-04-21 19:33         ` [dpdk-dev] [PATCH v5 3/3] net/pcap: build on Windows Dmitry Kozlyuk
2021-04-21 21:54         ` [dpdk-dev] [PATCH v5 0/3] " Thomas Monjalon

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