[profile] Allow interrupts to be excluded from profiling results

Interrupt processing adds noise to profiling results.  Allow
interrupts (from within protected mode) to be profiled separately,
with time spent within the interrupt handler being excluded from any
other profiling currently in progress.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 30 insertions, 3 deletions

diff --git a/src/arch/i386/transitions/librm_mgmt.c b/src/arch/i386/transitions/librm_mgmt.c
index f90d49b0..89668978 100644
--- a/src/arch/i386/transitions/librm_mgmt.c
+++ b/src/arch/i386/transitions/librm_mgmt.c
@@ -8,6 +8,7 @@
 FILE_LICENCE ( GPL2_OR_LATER );
 
 #include <stdint.h>
+#include <ipxe/profile.h>
 #include <realmode.h>
 #include <pic8259.h>
 
@@ -30,6 +31,12 @@ struct idtr idtr = {
 	.limit = ( sizeof ( idt ) - 1 ),
 };
 
+/** Timer interrupt profiler */
+static struct profiler timer_irq_profiler __profiler = { .name = "irq.timer" };
+
+/** Other interrupt profiler */
+static struct profiler other_irq_profiler __profiler = { .name = "irq.other" };
+
 /**
  * Allocate space on the real-mode stack and copy data there from a
  * user buffer
@@ -104,18 +111,38 @@ void init_idt ( void ) {
 }
 
 /**
+ * Determine interrupt profiler (for debugging)
+ *
+ * @v intr		Interrupt number
+ * @ret profiler	Profiler
+ */
+static struct profiler * interrupt_profiler ( int intr ) {
+
+	switch ( intr ) {
+	case IRQ_INT ( 0 ) :
+		return &timer_irq_profiler;
+	default:
+		return &other_irq_profiler;
+	}
+}
+
+/**
  * Interrupt handler
  *
- * @v irq		Interrupt number
+ * @v intr		Interrupt number
  */
-void __attribute__ (( cdecl, regparm ( 1 ) )) interrupt ( int irq ) {
+void __attribute__ (( cdecl, regparm ( 1 ) )) interrupt ( int intr ) {
+	struct profiler *profiler = interrupt_profiler ( intr );
 	uint32_t discard_eax;
 
 	/* Reissue interrupt in real mode */
+	profile_start ( profiler );
 	__asm__ __volatile__ ( REAL_CODE ( "movb %%al, %%cs:(1f + 1)\n\t"
 					   "\n1:\n\t"
 					   "int $0x00\n\t" )
-			       : "=a" ( discard_eax ) : "0" ( irq ) );
+			       : "=a" ( discard_eax ) : "0" ( intr ) );
+	profile_stop ( profiler );
+	profile_exclude ( profiler );
 }
 
 PROVIDE_UACCESS_INLINE ( librm, phys_to_user );