[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [RFC 1/6] xen/arm: Re-enable interrupt later in the trap path

Hello Julien,

On 30.07.19 23:10, Julien Grall wrote:

In this series I think I need interrupts locked until I start time accounting 
for hypervisor. Time accounting is started by `tacc_head()` function. I prefer 
to have it called from C, because it is more convenient and obvious for those 
who are less familiar with the ARM code.

Here is the question to you: what is the best place (and way) to start 
hypervisor time tracking?

Resending the patch without things addressed is only going to make it worst.

I'm still convinced the patch would improve interrupt latency for high 
interrupt rate use cases.
But I understand that I have no experiment to prove the effect, so I'm not 
willing to push through the patch.

The only thing I ask is justification in your commit message rather than 
throwing things and expecting the reviewer to understand why you do that. I 
would recommend to refresh yourself how to submit a patch series [1].

I'll follow you recommendation.

Also, I have a question to you about another aspect of this patch. In the 
function `enter_hypervisor_head()` there is a check for a disabled workaround 
and turning it on. If we have the interrupts enabled until there, we have good 
chances to go through the interrupt processing `do_IRQ()` before WA enabled. Is 
it still OK?

Hmmm, that's correct.

Sorry I did not get your point. What exactly is correct? My observation of the 
scenario where we can go through the big piece of the hypervisor without WA 
enabled? Or processing IRQs without WA enabled is the correct way to do?

Andrii Anisov.

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.