[coreboot] [PATCH] faster AP launch for recent AMD processors
Scott Duplichan
scott at notabs.org
Mon Oct 18 18:38:55 CEST 2010
To reduce boot time, removing the double startup IPI and 10 ms
delay from lapic_cpu_init.c should be considered. Because I can
test this code only on recent AMD cpu models, it is only safe
to apply the change in those cases. The following patch uses
a compile time check to identify CPUs where the change is known
to work. Would a runtime check be better?
Thanks,
Scott
Signed-off-by: Scott Duplichan <scott at notabs.org>
Index: src/cpu/x86/lapic/lapic_cpu_init.c
===================================================================
--- src/cpu/x86/lapic/lapic_cpu_init.c (revision 5965)
+++ src/cpu/x86/lapic/lapic_cpu_init.c (working copy)
@@ -113,7 +113,9 @@
}
return 0;
}
+ #if !defined (CONFIG_CPU_AMD_MODEL_10XXX) && !defined (CONFIG_CPU_AMD_MODEL_14XXX)
mdelay(10);
+ #endif
printk(BIOS_SPEW, "Deasserting INIT.\n");
@@ -144,6 +146,9 @@
#endif
num_starts = 2;
+ #if defined (CONFIG_CPU_AMD_MODEL_10XXX) || defined (CONFIG_CPU_AMD_MODEL_14XXX)
+ num_starts = 1;
+ #endif
/*
* Run STARTUP IPI loop.
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