[V6 05/11] powerpc, perf: Re-arrange BHRB processing

From: Anshuman Khandual
Date: Wed May 21 2014 - 06:03:58 EST


This patch cleans up some existing indentation problem and
re-organizes the BHRB processing code with an helper function
named `update_branch_entry` making it more readable. This patch
does not change any functionality.

Signed-off-by: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/perf/core-book3s.c | 102 ++++++++++++++++++++--------------------
1 file changed, 52 insertions(+), 50 deletions(-)

diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 4520c93..66bea54 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -402,11 +402,21 @@ static __u64 power_pmu_bhrb_to(u64 addr)
return target - (unsigned long)&instr + addr;
}

+/* Update individual branch entry */
+void update_branch_entry(struct cpu_hw_events *cpuhw, int u_index, u64 from, u64 to, int pred)
+{
+ cpuhw->bhrb_entries[u_index].from = from;
+ cpuhw->bhrb_entries[u_index].to = to;
+ cpuhw->bhrb_entries[u_index].mispred = pred;
+ cpuhw->bhrb_entries[u_index].predicted = ~pred;
+ return;
+}
+
/* Processing BHRB entries */
void power_pmu_bhrb_read(struct cpu_hw_events *cpuhw)
{
u64 val;
- u64 addr;
+ u64 addr, tmp;
int r_index, u_index, pred;

r_index = 0;
@@ -417,62 +427,54 @@ void power_pmu_bhrb_read(struct cpu_hw_events *cpuhw)
if (!val)
/* Terminal marker: End of valid BHRB entries */
break;
- else {
- addr = val & BHRB_EA;
- pred = val & BHRB_PREDICTION;

- if (!addr)
- /* invalid entry */
- continue;
+ addr = val & BHRB_EA;
+ pred = val & BHRB_PREDICTION;

- /* Branches are read most recent first (ie. mfbhrb 0 is
- * the most recent branch).
- * There are two types of valid entries:
- * 1) a target entry which is the to address of a
- * computed goto like a blr,bctr,btar. The next
- * entry read from the bhrb will be branch
- * corresponding to this target (ie. the actual
- * blr/bctr/btar instruction).
- * 2) a from address which is an actual branch. If a
- * target entry proceeds this, then this is the
- * matching branch for that target. If this is not
- * following a target entry, then this is a branch
- * where the target is given as an immediate field
- * in the instruction (ie. an i or b form branch).
- * In this case we need to read the instruction from
- * memory to determine the target/to address.
+ if (!addr)
+ /* invalid entry */
+ continue;
+
+ /* Branches are read most recent first (ie. mfbhrb 0 is
+ * the most recent branch).
+ * There are two types of valid entries:
+ * 1) a target entry which is the to address of a
+ * computed goto like a blr,bctr,btar. The next
+ * entry read from the bhrb will be branch
+ * corresponding to this target (ie. the actual
+ * blr/bctr/btar instruction).
+ * 2) a from address which is an actual branch. If a
+ * target entry proceeds this, then this is the
+ * matching branch for that target. If this is not
+ * following a target entry, then this is a branch
+ * where the target is given as an immediate field
+ * in the instruction (ie. an i or b form branch).
+ * In this case we need to read the instruction from
+ * memory to determine the target/to address.
+ */
+ if (val & BHRB_TARGET) {
+ /* Target branches use two entries
+ * (ie. computed gotos/XL form)
*/
+ tmp = addr;

+ /* Get from address in next entry */
+ val = read_bhrb(r_index++);
+ addr = val & BHRB_EA;
if (val & BHRB_TARGET) {
- /* Target branches use two entries
- * (ie. computed gotos/XL form)
- */
- cpuhw->bhrb_entries[u_index].to = addr;
- cpuhw->bhrb_entries[u_index].mispred = pred;
- cpuhw->bhrb_entries[u_index].predicted = ~pred;
-
- /* Get from address in next entry */
- val = read_bhrb(r_index++);
- addr = val & BHRB_EA;
- if (val & BHRB_TARGET) {
- /* Shouldn't have two targets in a
- row.. Reset index and try again */
- r_index--;
- addr = 0;
- }
- cpuhw->bhrb_entries[u_index].from = addr;
- } else {
- /* Branches to immediate field
- (ie I or B form) */
- cpuhw->bhrb_entries[u_index].from = addr;
- cpuhw->bhrb_entries[u_index].to =
- power_pmu_bhrb_to(addr);
- cpuhw->bhrb_entries[u_index].mispred = pred;
- cpuhw->bhrb_entries[u_index].predicted = ~pred;
+ /* Shouldn't have two targets in a
+ row.. Reset index and try again */
+ r_index--;
+ addr = 0;
}
- u_index++;
-
+ update_branch_entry(cpuhw, u_index, addr, tmp, pred);
+ } else {
+ /* Branches to immediate field
+ (ie I or B form) */
+ tmp = power_pmu_bhrb_to(addr);
+ update_branch_entry(cpuhw, u_index, addr, tmp, pred);
}
+ u_index++;
}
cpuhw->bhrb_stack.nr = u_index;
return;
--
1.7.11.7

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