[Skiboot] [PATCH v5 8/9] nest sampling rate workaround
Madhavan Srinivasan
maddy at linux.vnet.ibm.com
Thu Sep 3 19:22:35 AEST 2015
HW325868 showed that the default sampling rate used by slw ima microcode
does not fetch any mcs write counter values. After a lot of experiments,
sampling rate of 64ms was found to be effective. Accordingly, set the new sample
rate before starting the engine.
Signed-off-by: Madhavan Srinivasan <maddy at linux.vnet.ibm.com>
---
hw/nest.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/hw/nest.c b/hw/nest.c
index 03f5e9c952c0..6bc0abe7ddf4 100644
--- a/hw/nest.c
+++ b/hw/nest.c
@@ -456,6 +456,15 @@ void nest_pmu_init(int loaded)
prerror("nest-counters: Unknown chip type, skipping dimm file\n");
break;
}
+
+ /*
+ * Work around for HW325868: modify the sampling rate
+ * since the default sampling rate of 128us does not
+ * fetch any mcs write data. Update the new sampling rate
+ * of 64ms before starting the engine.
+ */
+ addr = chip->homer_base + CB_STRUCT_SPEED;
+ out_be64((u64 *)addr, SLW_IMA_SAMPLE_RATE_64MS);
}
return;
--
1.9.1
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