From: "Mattias Rönnblom" <hofors@lysator.liu.se>
To: "Morten Brørup" <mb@smartsharesystems.com>,
"Stephen Hemminger" <stephen@networkplumber.org>
Cc: "Ferruh Yigit" <ferruh.yigit@amd.com>,
"Thomas Monjalon" <thomas@monjalon.net>,
"Andrew Rybchenko" <andrew.rybchenko@oktetlabs.ru>,
dev@dpdk.org, stable@dpdk.org,
"Mattias Rönnblom" <mattias.ronnblom@ericsson.com>
Subject: Re: [PATCH] ethdev: document that stats reset APIs are not thread-safe
Date: Sun, 28 Apr 2024 17:52:46 +0200 [thread overview]
Message-ID: <1a65e90a-a54b-4584-bc00-a568d7c11f78@lysator.liu.se> (raw)
In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC35E9F3FA@smartserver.smartshare.dk>
On 2024-04-26 17:17, Morten Brørup wrote:
>> From: Stephen Hemminger [mailto:stephen@networkplumber.org]
>> Sent: Friday, 26 April 2024 17.14
>>
>> On Fri, 26 Apr 2024 14:20:01 +0200
>> Morten Brørup <mb@smartsharesystems.com> wrote:
>>
>>>> From: Ferruh Yigit [mailto:ferruh.yigit@amd.com]
>>>> Sent: Thursday, 25 April 2024 18.53
>>>>
>>>> Making 'rte_eth_stats_reset()' and 'rte_eth_xstats_reset()' APIs thread
>>>> safe has performance impact on datapath.
>>>>
>>>> Instead document APIs as not thread safe and add condition for reliable
>>>> stats reset functionality, forwarding should be stopped.
>>>
>>> I'm not sure stopping forwarding suffices.
>>> NIC hardware counters will keep progressing unless RX and TX is stopped at
>> NIC level.
>>>
>>> I don't have any suggestions for a better wording, though. :-(
>>>
>>> Anyway, better with the patch than without...
>>> Acked-by: Morten Brørup <mb@smartsharesystems.com>
>>>
>>
>> The safest option would be:
>> rte_eth_dev_stop
>> rte_eth_stats_reset
>> rte_eth_dev_start
>
> Yes, but this will cause packet loss.
> Network admins should be able to clear the counters without causing packet loss.
>
For sure, and they would do it via some O&M interface, which would in
turn talk the control plane, which in turn would talk to the data plane
(including <rte_ethdev.h>).
Either the control plane or the O&M layer could keep track of a reset
offset. Doesn't have to be on the PMD level.
next prev parent reply other threads:[~2024-04-28 15:52 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-25 16:53 Ferruh Yigit
2024-04-26 12:20 ` Morten Brørup
2024-04-26 15:13 ` Stephen Hemminger
2024-04-26 15:17 ` Morten Brørup
2024-04-26 22:57 ` Stephen Hemminger
2024-04-28 15:52 ` Mattias Rönnblom [this message]
2024-04-29 6:20 ` Morten Brørup
2024-04-29 15:33 ` Stephen Hemminger
2024-04-28 15:48 ` Mattias Rönnblom
2024-04-29 7:57 ` Morten Brørup
2024-04-29 9:30 ` Mattias Rönnblom
2024-04-26 21:33 ` Patrick Robb
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