[PATCH 1/4] perf,x86: De-obfuscate HSW offcore bits

From: Peter Zijlstra
Date: Thu Oct 23 2014 - 07:00:05 EST


Andi introduced the HSW cache events array, but used magic constants
against convention as set by all the other uarchs. Try and deobfuscate
these a bit.

This patch should not change the actual values generated; however
weird they seems.

In that patch Andi also said there were differences between the
SNB/IVB and HSW/BDW offcore tables but failed to specify which and
why.

Fixes: 86a349a28b24 ("perf/x86/intel: Add Broadwell core support")
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-@xxxxxxxxxxxxxx
---
arch/x86/kernel/cpu/perf_event_intel.c | 48 +++++++++++++++++++++++++++------
1 file changed, 40 insertions(+), 8 deletions(-)

--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -247,6 +247,7 @@ static u64 intel_pmu_event_map(int hw_ev
#define SNB_BUS_LOCKS (1ULL << 10)
#define SNB_STRM_ST (1ULL << 11)
#define SNB_OTHER (1ULL << 15)
+
#define SNB_RESP_ANY (1ULL << 16)
#define SNB_NO_SUPP (1ULL << 17)
#define SNB_LLC_HITM (1ULL << 18)
@@ -255,6 +256,7 @@ static u64 intel_pmu_event_map(int hw_ev
#define SNB_LLC_HITF (1ULL << 21)
#define SNB_LOCAL (1ULL << 22)
#define SNB_REMOTE (0xffULL << 23)
+
#define SNB_SNP_NONE (1ULL << 31)
#define SNB_SNP_NOT_NEEDED (1ULL << 32)
#define SNB_SNP_MISS (1ULL << 33)
@@ -519,6 +521,40 @@ static __initconst const u64 hsw_hw_cach
},
};

+/* HSW Request type */
+#define HSW_DMND_DATA_RD (1ULL << 0)
+#define HSW_DMND_RFO (1ULL << 1)
+#define HSW_DMND_IFETCH (1ULL << 2)
+
+#define HSW_PF_DATA_RD (1ULL << 4)
+#define HSW_PF_RFO (1ULL << 5)
+#define HSW_PF_IFETCH (1ULL << 6)
+
+#define HSW_OTHER (1ULL << 15)
+
+/* HSW Supplier info := SNB Supplier info */
+/* HSW Snoop Info := SNB Snoop Info */
+
+/*
+ * SNB_LLC_* is specified as 'reserved' in the SDM
+ * but Andi added it anyhow, suggesting HSW/BDW have it just fine
+ *
+ * XXX NHM/WSM/SNB/IVB don't have the PF/IFETCH bits set
+ */
+#define HSW_DMND_READ (HSW_DMND_DATA_RD|HSW_DMND_IFETCH| \
+ HSW_PF_DATA_RD|HSW_PF_IFETCH| \
+ SNB_LLC_DATA_RD|SNB_LLC_IFETCH)
+
+/* XXX NHM/WSM/SNB/IVB dont have the PF bits set */
+#define HSW_DMND_WRITE (HSW_DMND_RFO|HSW_PF_RFO|SNB_LLC_RFO)
+
+#define HSW_DMND_PREFETCH (0) /* XXX broken ? */
+
+#define HSW_DRAM_ANY (SNB_NO_SUPP|SNB_SNP_ANY|(0x78ULL << 23)) /* WTF */
+
+#define HSW_L3_ACCESS (0) /* XXX no supplier! */
+#define NSW_L3_MISS (HSW_DRAM_ANY|SNB_NON_DRAM)
+
static __initconst const u64 hsw_hw_cache_extra_regs
[PERF_COUNT_HW_CACHE_MAX]
[PERF_COUNT_HW_CACHE_OP_MAX]
@@ -526,16 +562,12 @@ static __initconst const u64 hsw_hw_cach
{
[ C(LL ) ] = {
[ C(OP_READ) ] = {
- /* OFFCORE_RESPONSE:ALL_DATA_RD|ALL_CODE_RD */
- [ C(RESULT_ACCESS) ] = 0x2d5,
- /* OFFCORE_RESPONSE:ALL_DATA_RD|ALL_CODE_RD|SUPPLIER_NONE|
- L3_MISS|ANY_SNOOP */
- [ C(RESULT_MISS) ] = 0x3fbc0202d5ull,
+ [ C(RESULT_ACCESS) ] = HSW_DMND_READ|HSW_L3_ACCESS,
+ [ C(RESULT_MISS) ] = HSW_DMND_READ|HSW_L3_MISS,
},
[ C(OP_WRITE) ] = {
- [ C(RESULT_ACCESS) ] = 0x122, /* OFFCORE_RESPONSE:ALL_RFO */
- /* OFFCORE_RESPONSE:ALL_RFO|SUPPLIER_NONE|L3_MISS|ANY_SNOOP */
- [ C(RESULT_MISS) ] = 0x3fbc020122ull,
+ [ C(RESULT_ACCESS) ] = HSW_DMND_WRITE|HSW_L3_ACCESS,
+ [ C(RESULT_MISS) ] = HSW_DMND_WRITE|HSW_L3_MISS,
},
[ C(OP_PREFETCH) ] = {
[ C(RESULT_ACCESS) ] = 0x0,


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