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From: David Ahern <dsahern@gmail.com>
To: Alarig Le Lay <alarig@swordarmor.fr>
Cc: netdev@vger.kernel.org, jack@basilfillan.uk,
	Vincent Bernat <bernat@debian.org>
Subject: Re: IPv6 regression introduced by commit 3b6761d18bc11f2af2a6fc494e9026d39593f22c
Date: Tue, 10 Mar 2020 09:27:53 -0600	[thread overview]
Message-ID: <92f8ca32-af23-effd-55d8-8d1065f644f8@gmail.com> (raw)
In-Reply-To: <20200310103541.aplhwhfsvcflczhp@mew.swordarmor.fr>

On 3/10/20 4:35 AM, Alarig Le Lay wrote:
> On dim.  8 mars 20:15:14 2020, David Ahern wrote:
>> If you are using x86 based CPU you can do this:
>>     perf probe ip6_dst_alloc%return ret=%ax
>>
>>     perf record -e probe:* -a -g -- sleep 10
>>     --> run this during the flapping
>>
>>     perf script
> 
> For this probe I see that: https://paste.swordarmor.fr/raw/pt9b

none of the dst allocations are failing.

Are the failing windows always ~30 seconds long?


> 
>> this will show if the flapping is due to dst alloc failures.
>>
>> Other things to try:
>>     perf probe ip6_dst_gc
>>     perf stat -e probe:* -a -I 1000
>>     --> will show calls/sec to running dst gc
> 
> https://paste.swordarmor.fr/raw/uBnm

This is not lining up with dst allocations above. gc function is only
invoked from dst_alloc, and for ipv6 all dst allocations go through
ip6_dst_alloc.

> 
>>     perf probe __ip6_rt_update_pmtu
>>     perf stat -e probe:* -a -I 1000
>>     --> will show calls/sec to mtu updating
> 
> This probe always stays at 0 even when the NDP is failing.
>  
>>     perf probe rt6_insert_exception
>>     perf state -e probe:* -a -I 1000
>>     --> shows calls/sec to inserting exceptions
> 
> Same as the last one.

so no exception handling.

How many ipv6 sockets are open? (ss -6tpn)

How many ipv6 neighbor entries exist? (ip -6 neigh sh)

  reply	other threads:[~2020-03-10 15:27 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-05  8:17 Alarig Le Lay
2020-03-08  0:52 ` David Ahern
2020-03-08 10:57   ` Alarig Le Lay
2020-03-09  2:15     ` David Ahern
2020-03-09  8:59       ` Fabian Grünbichler
2020-03-09 10:47         ` Alarig Le Lay
2020-03-09 11:35           ` Fabian Grünbichler
2020-03-10 10:35       ` Alarig Le Lay
2020-03-10 15:27         ` David Ahern [this message]
2020-03-29 14:09           ` Alarig Le Lay
2020-09-27 15:35   ` Baptiste Jonglez
2020-09-27 16:10     ` Baptiste Jonglez
2020-09-28  3:38       ` David Ahern
2020-09-28  5:39         ` Vincent Bernat
2020-09-28  6:48         ` Baptiste Jonglez
2020-09-29  3:39           ` David Ahern

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