----- Original Message -----

From: "Xavi Hernandez" <[email protected]> 
To: "Ashish Pandey" <[email protected]> 
Cc: "Amar Tumballi Suryanarayan" <[email protected]>, "gluster-devel" 
<[email protected]> 
Sent: Thursday, May 30, 2019 2:03:54 PM 
Subject: Re: [Gluster-devel] Should we enable features.locks-notify.contention 
by default ? 

On Thu, May 30, 2019 at 9:03 AM Ashish Pandey < [email protected] > wrote: 





I am only concerned about in-service upgrade. 
If a feature/option is not present in V1, then I would prefer not to enable it 
by default on V2. 




The problem is that without enabling it, (other-)eager-lock will cause 
performance issues in some cases. It doesn't seem good to keep an option 
disabled if enabling it solves these problems. 


<blockquote>

We have seen some problem in other-eager-lock when we changed it to enable by 
default. 

</blockquote>


Which problems ? I think the only issue with other-eager-lock has been 
precisely that locks-notify-contention was disabled and a bug that needed to be 
solved anyway. 
I was talking about the issue when we have other-eager-lock disabled and then 
try to do in-service upgrade to a version where this option is ON by default. 
Although we don't have root cause of that, I was wondering if similar issue 
could happen in this case also. 

The difference will be that upgraded bricks will start sending upcall 
notifications. If clients are too old, these will simply be ignored. So I don't 
see any problem right now. 

Am I missing something ? 


<blockquote>


--- 
Ashish 


From: "Amar Tumballi Suryanarayan" < [email protected] > 
To: "Xavi Hernandez" < [email protected] > 
Cc: "gluster-devel" < [email protected] > 
Sent: Thursday, May 30, 2019 12:04:43 PM 
Subject: Re: [Gluster-devel] Should we enable features.locks-notify.contention 
by default ? 



On Thu, May 30, 2019 at 11:34 AM Xavi Hernandez < [email protected] > 
wrote: 

<blockquote>

Hi all, 

a patch [1] was added some time ago to send upcall notifications from the locks 
xlator to the current owner of a granted lock when another client tries to 
acquire the same lock (inodelk or entrylk). This makes it possible to use 
eager-locking on the client side, which improves performance significantly, 
while also keeping good performance when multiple clients are accessing the 
same files (the current owner of the lock receives the notification and 
releases it as soon as possible, allowing the other client to acquire it and 
proceed very soon). 

Currently both AFR and EC are ready to handle these contention notifications 
and both use eager-locking. However the upcall contention notification is 
disabled by default. 

I think we should enabled it by default. Does anyone see any possible issue if 
we do that ? 


</blockquote>


If it helps performance, we should ideally do it. 

But, considering we are days away from glusterfs-7.0 branching, should we do it 
now, or wait for branch out, and make it default for next version? (so that it 
gets time for testing). Considering it is about consistency I would like to 
hear everyone's opinion here. 

Regards, 
Amar 



<blockquote>


Regards, 

Xavi 

[1] https://review.gluster.org/c/glusterfs/+/14736 
_______________________________________________ 


</blockquote>


-- 
Amar Tumballi (amarts) 

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</blockquote>


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