RE: [PATCH 1/1] inside-secure irq balance

From: "Van Leeuwen, Pascal" <pvanleeuwen@rambus.com>
To: Sven Auhagen <sven.auhagen@voleatech.de>,
	Herbert Xu <herbert@gondor.apana.org.au>
Cc: "linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>
Subject: RE: [PATCH 1/1] inside-secure irq balance
Date: Fri, 17 Jul 2020 08:56:07 +0000	[thread overview]
Message-ID: <CY4PR0401MB3652ED2BFC2833ACCB272868C37C0@CY4PR0401MB3652.namprd04.prod.outlook.com> (raw)
In-Reply-To: <20200717075334.vg7nvidds25f5ltb@SvensMacBookAir.hq.voleatech.com>

> -----Original Message-----
> From: Sven Auhagen <sven.auhagen@voleatech.de>
> Sent: Friday, July 17, 2020 9:54 AM
> To: Herbert Xu <herbert@gondor.apana.org.au>
> Cc: Van Leeuwen, Pascal <pvanleeuwen@rambus.com>; linux-crypto@vger.kernel.org
> Subject: Re: [PATCH 1/1] inside-secure irq balance
>
> <<< External Email >>>
> On Fri, Jul 17, 2020 at 04:57:38PM +1000, Herbert Xu wrote:
> > On Fri, Jul 17, 2020 at 08:35:04AM +0200, Sven Auhagen wrote:
> > >
> > > I disagree as this is common practice among other kernel drivers
> > > like ethernet.
> > > Also this is also beeing done in other crypto drivers not to say
> > > that the speed improvements are pretty significant.
> > >
> > > irqbalance can of course also do the job but there is no downside
> > > of adding the irq hint in the driver.
> >
> > If you're going to do this please at least use the function
> > cpumask_local_spread.
>
> I do not have access to a numa node inside the inside secure
> driver and can only use -1 as the cpumask_local_spread numa node.
> Is that what you are looking for?
>
Now I am no expert on all this kernel IRQ balancing stuff, so I'm not going to
comment on how to do it or what is appropriate.

But I do want to emphasize that this patch is in line with how the hardware
was intended to be used i.e. have each ring handled by a dedicated CPU.

Also, you have to keep in mind that this driver does not have to run on
every possible system out there, it ONLY needs to run on those particular
SOC's that actually embed this hardware IP. And I know exactly which ones,
since it all has to go through me first :-) It only ever runs on embedded
CPU clusters (ARM, MIPS, Atom and C-Sky), no need to worry about NUMA
nodes.

> Best
> Sven
>
> >
> > Thanks,
> > --
> > Email: Herbert Xu <herbert@gondor.apana.org.au>
> > Home Page:
> https://eur03.safelinks.protection.outlook.com/?url=http:%2F%2Fgondor.apana.org.au%2F~herbert%2F&amp;data=02%7C01%7Csve
> n.auhagen%40voleatech.de%7C11ec864588ea43cb2b5508d82a1eb424%7Cb82a99f679814a7295344d35298f847b%7C0%7C1%7C6373056
> 58666145675&amp;sdata=U0TRKq1keey2jogZyelLwvwfSpj4SavJAhumM63phs0%3D&amp;reserved=0
> > PGP Key:
> https://eur03.safelinks.protection.outlook.com/?url=http:%2F%2Fgondor.apana.org.au%2F~herbert%2Fpubkey.txt&amp;data=02%7
> C01%7Csven.auhagen%40voleatech.de%7C11ec864588ea43cb2b5508d82a1eb424%7Cb82a99f679814a7295344d35298f847b%7C0%7C1
> %7C637305658666155670&amp;sdata=FDSkrK3t9OMTaA%2FRxMcgKgqU4wVBx%2BomSA%2BUlZtNgBU%3D&amp;reserved=0

Regards,
Pascal van Leeuwen
Silicon IP Architect Multi-Protocol Engines, Rambus Security
Rambus ROTW Holding BV
+31-73 6581953

Note: The Inside Secure/Verimatrix Silicon IP team was recently acquired by Rambus.
Please be so kind to update your e-mail address book with my new e-mail address.

** This message and any attachments are for the sole use of the intended recipient(s). It may contain information that is confidential and privileged. If you are not the intended recipient of this message, you are prohibited from printing, copying, forwarding or saving it. Please delete the message and attachments and notify the sender immediately. **

Rambus Inc.<http://www.rambus.com>