Subject: Re: [PATCH net-2.6] Re: rib_trie / Fix inflate_threshold_root. Now=15 size=11 bits

From: Paweł Staszewski <[email-masked]>
Date: Thu, 09 Jul 2009 22:34:17 +0200

Jarek Poplawski pisze:
> On Wed, Jul 08, 2009 at 12:56:13AM +0200, Paweł Staszewski wrote:
>   
>> Jarek Poplawski pisze:
>>     
> ...
>   
>>> ---> (synchronize take 9; apply on top of the 2.6.29.x with the last
>>>   	all-in-one patch, or net-2.6)
>>>
>>>   
>>>       
>> Applied to 2.6.29.5 preempt/no-preempt and tested: - with preempt i make  
>> only one test with sync_pages = 256 to check that is working :)
>>
>> So here are some tests for different sync_pages size.
>>     
> ...
>   
>> So i see in prev tests i make something wrong in time counting
>> So i modify test script and make tests again:
>>
>> echo 64 > /sys/module/fib_trie/parameters/sync_pages
>> Total size reach max in 13 sec
>>
>> echo 128 > /sys/module/fib_trie/parameters/sync_pages
>> Total size reach max in 10 sec
>>
>> echo 256 > /sys/module/fib_trie/parameters/sync_pages
>> Total size reach max in 10 sec
>>
>> And for sync_paqges >256 time for propagating routes is always 10sec.
>>     
>
> So this means sync_pages 128 or 256 is reasonable.
>
>   
>> Also today i have many messages in dmesg like this:
>> Fix inflate_threshold_root. Now=25 size=11 bits
>> :)
>>     
>
>   
> This is something new and a bit surprising to me: the same threshold
> in previous tests didn't generate this? Do you mean more than: 
> "Fix inflate_threshold_root. Now=15 size=11 bits" before?
>
>   
Yes. Sorry for that - this info was not all the day but only 5 minutes 
when i was making tests.
This info was reported only when all iBGP peers was down/up fast.

>> And after tune :
>> /sys/module/fib_trie/parameters/inflate_threshold_root
>> no more info :)
>>     
>
> With what value?
>
>   
When i set 35 as inflate_threshold_root there was no info even if all 
iBGP peers was down/up.

But i start to search when i have info about "Fix inflate_threshold_root"
And i see that the best is set this to 20 for me i have no info then in 
normal router operation / without down/up bgp peers many times in short 
time.

> Pawel, let's say that current defaults are:
> inflate_threshold_root 25 sync_pages 256
>
> I'd like you to try to check if e.g.:
> inflate_threshold_root 15 sync_pages 256
> can give you any visible or subjective difference worth tweaking it
> at all? (These stats from the next messages don't show this enough.)
> You don't need to hurry with this...
>
>   
I will try to make more accurate tests in weekend.

Regards
Paweł Staszewski
> Thanks,
> Jarek P.