[ofw] [PATCH] affinity options

[Sean Hefty]

Can you provide any data that shows the benefit of this?  (I don't really care
what app, but maybe showing the improvement that IPoIB gets?)

 

  _____  

From: ofw-bounces at lists.openfabrics.org
[mailto:ofw-bounces at lists.openfabrics.org] On Behalf Of Slava Strebkov
Sent: Wednesday, April 02, 2008 7:47 AM
To: ofw at lists.openfabrics.org
Subject: [ofw] [PATCH] affinity options

 

Hi,

The following patch provides a way to user to specify the cpu affinity mask.

Setting the value of ProcessorAffinity to FFFFFFFF binds interrupt to last cpu
on machine.

 

Why do we need this special value, versus just some CPU index value?  In place
of FFFFFFFF, just use 0 to get the first. 

 

Index: hw/mthca/kernel/hca_pnp.c

===================================================================

--- hw/mthca/kernel/hca_pnp.c   (revision 1031)

+++ hw/mthca/kernel/hca_pnp.c (working copy)

@@ -678,6 +678,29 @@

                        if( pHcaRes->Type == CmResourceTypeInterrupt )

                        {

                                    p_ext->interruptInfo = *pHostRes;

+            if ( g_processor_affinity == 0xFFFFFFFF ) 

+                                  {

+                                              /* 

+                                              * Calculate the mask of the last
processor

+                                              */

+                                              KAFFINITY
n_active_processors_bitmask;

+                                              uint32_t
last_processor_mask = 0 , tmp_processor_mask = 1;

+                                              

+                                              n_active_processors_bitmask =
KeQueryActiveProcessors();

+                while ( tmp_processor_mask & n_active_processors_bitmask )

+                                              {

+
last_processor_mask = tmp_processor_mask;

+
tmp_processor_mask = tmp_processor_mask << 1;

+                                              }

+
p_ext->interruptInfo.u.Interrupt.Affinity = last_processor_mask; 

+                                  }

+                                  else if (g_processor_affinity != 0) 

+                                  {

+
p_ext->interruptInfo.u.Interrupt.Affinity = g_processor_affinity;


+                                  }

+                                  HCA_PRINT( TRACE_LEVEL_INFORMATION,
HCA_DBG_PNP,("Set Interrupt affinity to : 0x%08X\n",

+
(int)p_ext->interruptInfo.u.Interrupt.Affinity ));

+

 

This is separate from this patch, but can we agree on a common definition for
what a 'tab' is in this stack?

 

- Sean

 

 

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