Template Version: @(#)sac_nextcase 1.68 02/23/09 SMI
This information is Copyright 2009 Sun Microsystems
1. Introduction
1.1. Project/Component Working Name:
IRM Framework Extension(s)
1.2. Name of Document Author/Supplier:
Author: Prasad Singamsetty
1.3 Date of This Document:
21 September, 2009
4. Technical Description
IRM Framework Extension(s)
1.0 Introduction
PSARC/2008/628 introduced the generic Interrupt Resource Management
(IRM) feature and it was enabled on SPARC platforms. It also defined
DDI and NDI interfaces necessary for creating and managing interrupt
resource pool(s). But this feature was not enabled or delivered
for x86 platforms.
On x86 platforms, the global interrupt resources (vectors) are
associated with the local APIC (Advanced Programmable Interrupt
Controller) which is a component of CPU. So, the number of
interrupt resources in the system scales with the number of
CPUs present in the system. Since the number of CPUs present
in the system can dynamically change due to CPU hot-plug,
CPU offlineing, etc., the available interrupt resource pool
can change dynamically. In the current IRM framework there is
no interface defined to allow the IRM pool to be resized
dynamically.
This project will define the additional interface(s) needed in the
generic IRM framework and support the IRM feature on x86 platforms.
2.0 Problem
Dynamic resizing of IRM pool is not supported with the current
IRM framework. This is necessary to enable IRM feature on
x86 platforms.
3.0 Technical Details
A new NDI interface will be added to the IRM framework that
would allow dynamic resizing of an IRM pool by the platform
specific nexus drivers. This interface will be available for
both x86 and SPARC platforms but it is not needed on SPARC
at this time.
int ndi_irm_resize_pool(ddi_irm_pool_t *poolp, uint_t size);
poolp Pointer to IRM pool
size New total number of available vectors
in the pool (i.e. new value for ipool_totsz)
The ndi_irm_resize_pool() function will reset the pool size
to the specified value. If the new pool size is reduced from the
previous size then it may trigger resource re-balancing
operation by IRM if the number of free vectors is less
than the reduction in pool size.
4.0 Interfaces
This project exports the following interfaces:
Interface Classification Comments
-------------------------------------------------------------------
ndi_irm_resize_pool Consol. Private Resize the pool
-------------------------------------------------------------------
5.0 Release Summary
Solaris Next, S10 Update
Micro/Patch Release
6.0 Man Pages
6.1 ndi_irm_resize_pool
NAME
ndi_irm_resize_pool - resize the pool size
SYNOPSIS
#include <sys/types.h>
#include <sys/ddi.h>
#include <sys/sunndi.h>
int ndi_irm_resize_pool(ddi_irm_pool_t *poolp, uint_t size);
INTERFACE LEVEL
ON Consolidation Private
PARAMETERS
poolp Pointer to IRM pool
size New total number of available vectors in the pool
(i.e. new value for ipool_totsz)
The ndi_irm_resize_pool() function will reset the pool size
to the specified value. If the new pool size is reduced from the
previous size then it may trigger resource re-balancing operation
by IRM.
RETURN VALUES
DDI_SUCCESS on success
DDI_EINVAL invalid parameters
DDI_FAILURE failure to resize the pool
(e.g: rebalance operation failed)
PLATFORMS
x86, SPARC
7.0 Dependencies
Enabling IRM feature on x86 platforms is done as a follow on
work to the following RFE:
CR 6669984 Solaris x86 need to provide large number of interrupt vectors
for MSI/MSI-X
The reason for this dependency is the inherent limitations on the
current implementation of pcplusmp module (APIC module) where the
number of vectors available for each interrupt priority level (IPL)
is limited to 32, 16 or less in the system. So, having an IRM feature
on the current implementation adds no value to the system.
NOTE: The current plan is to integrate IRM feature along with
the APIC code changes for the above RFE.
8.0 References
[1] Interrupt Resource Management
http://sac.sfbay/PSARC/2008/628/
[2] Advanced DDI Interrupt Framework
http://sac.eng/arc/PSARC/2004/253/
6. Resources and Schedule
6.4. Steering Committee requested information
6.4.1. Consolidation C-team Name:
ON
6.5. ARC review type: FastTrack
6.6. ARC Exposure: open
