[PATCH] powerpc/booke64: Configurable lazy interrupt disabling

2012-01-18 Thread Laurentiu Tudor
This patch adds a menuconfig option that allows controlling the lazy interrupt disabling feature implemented by this commit: commit d04c56f73c30a5e593202ecfcf25ed43d42363a2 Author: Paul Mackerras Date: Wed Oct 4 16:47:49 2006 +1000 [POWERPC] Lazy interrupt disabling for 64-bit machines The

Re: [PATCH] powerpc/booke64: Configurable lazy interrupt disabling

2012-01-18 Thread Benjamin Herrenschmidt
On Wed, 2012-01-18 at 16:35 +0200, Laurentiu Tudor wrote: > This patch adds a menuconfig option that allows controlling > the lazy interrupt disabling feature implemented by this > commit: > > commit d04c56f73c30a5e593202ecfcf25ed43d42363a2 > Author: Paul Mackerras > Date: Wed Oct 4 16:47:49 200

Re: [PATCH] powerpc/booke64: Configurable lazy interrupt disabling

2012-01-19 Thread Tudor Laurentiu
Hi Ben, On 01/18/2012 11:10 PM, Benjamin Herrenschmidt wrote: On Wed, 2012-01-18 at 16:35 +0200, Laurentiu Tudor wrote: This patch adds a menuconfig option that allows controlling the lazy interrupt disabling feature implemented by this commit: commit d04c56f73c30a5e593202ecfcf25ed43d42363a2 A

Re: [PATCH] powerpc/booke64: Configurable lazy interrupt disabling

2012-01-19 Thread Stuart Yoder
On Wed, Jan 18, 2012 at 3:10 PM, Benjamin Herrenschmidt wrote: > On Wed, 2012-01-18 at 16:35 +0200, Laurentiu Tudor wrote: >> This patch adds a menuconfig option that allows controlling >> the lazy interrupt disabling feature implemented by this >> commit: >> >> commit d04c56f73c30a5e593202ecfcf25

Re: [PATCH] powerpc/booke64: Configurable lazy interrupt disabling

2012-01-19 Thread Stuart Yoder
On Thu, Jan 19, 2012 at 1:21 PM, Stuart Yoder wrote: > On Wed, Jan 18, 2012 at 3:10 PM, Benjamin Herrenschmidt > wrote: >> On Wed, 2012-01-18 at 16:35 +0200, Laurentiu Tudor wrote: >>> This patch adds a menuconfig option that allows controlling >>> the lazy interrupt disabling feature implemented

Re: [PATCH] powerpc/booke64: Configurable lazy interrupt disabling

2012-01-20 Thread Benjamin Herrenschmidt
> With Topaz, interrupts go directly to guests and we don't want to require a > trap/hcall to do an IACK, as that adds potentially thousands of cycles of > latency to every interrupt. > > As you know, with external proxy interrupts are acknowledged by the > hardware and it becomes problematic to

Re: [PATCH] powerpc/booke64: Configurable lazy interrupt disabling

2012-01-20 Thread Benjamin Herrenschmidt
On Thu, 2012-01-19 at 13:29 -0600, Stuart Yoder wrote: > Also, Scott had posted an approach to do option #2 a while back, > but as I recall there was some negative feedback about this. See: > I see... the problems with door

Re: [PATCH] powerpc/booke64: Configurable lazy interrupt disabling

2012-01-23 Thread Scott Wood
On 01/20/2012 05:05 PM, Benjamin Herrenschmidt wrote: > On Thu, 2012-01-19 at 13:29 -0600, Stuart Yoder wrote: >> Also, Scott had posted an approach to do option #2 a while back, >> but as I recall there was some negative feedback about this. See: >>

Re: [PATCH] powerpc/booke64: Configurable lazy interrupt disabling

2012-01-23 Thread Scott Wood
On 01/20/2012 05:02 PM, Benjamin Herrenschmidt wrote: > >> With Topaz, interrupts go directly to guests and we don't want to require a >> trap/hcall to do an IACK, as that adds potentially thousands of cycles of >> latency to every interrupt. >> >> As you know, with external proxy interrupts are a

Re: [PATCH] powerpc/booke64: Configurable lazy interrupt disabling

2012-01-23 Thread Benjamin Herrenschmidt
On Mon, 2012-01-23 at 13:21 -0600, Scott Wood wrote: > > BTW, for non-booke, when is DEC checked when interrupts are hard-enabled > > as part of exception return? Likewise with the PS3 HV thing. I only > > see the iseries check in the exception path. Exception return restores them to their prev

Re: [PATCH] powerpc/booke64: Configurable lazy interrupt disabling

2012-01-25 Thread Tudor Laurentiu
On 01/23/2012 10:50 PM, Benjamin Herrenschmidt wrote: On Mon, 2012-01-23 at 13:21 -0600, Scott Wood wrote: BTW, for non-booke, when is DEC checked when interrupts are hard-enabled as part of exception return? Likewise with the PS3 HV thing. I only see the iseries check in the exception path.

Re: [PATCH] powerpc/booke64: Configurable lazy interrupt disabling

2012-01-30 Thread Scott Wood
On 01/23/2012 02:50 PM, Benjamin Herrenschmidt wrote: > On Mon, 2012-01-23 at 13:21 -0600, Scott Wood wrote: >> Perhaps the issues with a higher priority interrupt intervening can be >> addressed by messing around with current task priority at the MPIC (with >> an hcall introduced for the hv case,

Re: [PATCH] powerpc/booke64: Configurable lazy interrupt disabling

2012-01-30 Thread Benjamin Herrenschmidt
On Mon, 2012-01-30 at 15:47 -0600, Scott Wood wrote: > Only the first one will happen in a context where we want to store. The > issue is if we get another higher priority interrupt when we enable, and > that enables interrupts and we get the doorbell that wants to run the > saved irq. If we get

Re: [PATCH] powerpc/booke64: Configurable lazy interrupt disabling

2012-01-30 Thread Scott Wood
On 01/30/2012 04:15 PM, Benjamin Herrenschmidt wrote: > On Mon, 2012-01-30 at 15:47 -0600, Scott Wood wrote: > >> Only the first one will happen in a context where we want to store. The >> issue is if we get another higher priority interrupt when we enable, and >> that enables interrupts and we g