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From: Alarig Le Lay <alarig@swordarmor.fr>
To: David Ahern <dsahern@gmail.com>
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 11:35:41 +0100	[thread overview]
Message-ID: <20200310103541.aplhwhfsvcflczhp@mew.swordarmor.fr> (raw)
In-Reply-To: <27457094-b62a-f029-e259-f7a274fee49d@gmail.com>

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

> 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

>     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.

> (in each you can remove the previous probe using 'perf probe -d <name>'
> or use -e <exact name> to only see data for the one event).
> 
> > I have the problem with 5.3 (proxmox 6), so unless FIB handling has been
> > changed since then, I doubt that it will works, but I will try on
> > Monday.
> > 
> 
> a fair amount of changes went in through 5.4 including improvements to
> neighbor handling. 5.4 (I think) also had changes around dumping the
> route cache.

Regards,
-- 
Alarig

  parent reply	other threads:[~2020-03-10 10:45 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 [this message]
2020-03-10 15:27         ` David Ahern
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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