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Message-ID: <20150807083428.GB18673@twins.programming.kicks-ass.net>
Date: Fri, 7 Aug 2015 10:34:28 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Andy Lutomirski <luto@...capital.net>
Cc: "Liang, Kan" <kan.liang@...el.com>,
Thomas Gleixner <tglx@...utronix.de>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"H. Peter Anvin" <hpa@...or.com>,
Andrew Lutomirski <luto@...nel.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Ingo Molnar <mingo@...nel.org>,
"linux-tip-commits@...r.kernel.org"
<linux-tip-commits@...r.kernel.org>
Subject: Re: [tip:perf/core] perf/x86: Add an MSR PMU driver
On Thu, Aug 06, 2015 at 05:59:43PM +0200, Peter Zijlstra wrote:
> On Thu, Aug 06, 2015 at 08:30:08AM -0700, Andy Lutomirski wrote:
> > On Thu, Aug 6, 2015 at 8:21 AM, Peter Zijlstra <peterz@...radead.org> wrote:
> > > On Tue, Aug 04, 2015 at 08:39:27PM +0000, Liang, Kan wrote:
> > > - default:
> > > - err = -ENOTSUPP;
> > > + if (!msr[i].test() || rdmsrl_safe(msr[i].msr, &val))
> > > + msr[i].attr = NULL;
> >
> > IIRC rdmsrl_safe literally never fails under QEMU TCG, and I'm not
>
> *sigh* the borkage never stops does it :-(
>
> > entirely sure what happens under KVM if emulation kicks in. It might
> > pay to keep the model check for the non-architectural stuff, or at
> > least check for a nonzero return value.
>
> Of course, 0 might be a valid value.. Esp. for the SMI counter.
This then..
---
arch/x86/kernel/cpu/perf_event_msr.c | 170 +++++++++++++++++------------------
1 file changed, 85 insertions(+), 85 deletions(-)
--- a/arch/x86/kernel/cpu/perf_event_msr.c
+++ b/arch/x86/kernel/cpu/perf_event_msr.c
@@ -10,17 +10,63 @@ enum perf_msr_id {
PERF_MSR_EVENT_MAX,
};
+bool test_aperfmperf(int idx)
+{
+ return boot_cpu_has(X86_FEATURE_APERFMPERF);
+}
+
+bool test_intel(int idx)
+{
+ if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL ||
+ boot_cpu_data.x86 != 6)
+ return false;
+
+ switch (boot_cpu_data.x86_model) {
+ case 30: /* 45nm Nehalem */
+ case 26: /* 45nm Nehalem-EP */
+ case 46: /* 45nm Nehalem-EX */
+
+ case 37: /* 32nm Westmere */
+ case 44: /* 32nm Westmere-EP */
+ case 47: /* 32nm Westmere-EX */
+
+ case 42: /* 32nm SandyBridge */
+ case 45: /* 32nm SandyBridge-E/EN/EP */
+
+ case 58: /* 22nm IvyBridge */
+ case 62: /* 22nm IvyBridge-EP/EX */
+
+ case 60: /* 22nm Haswell Core */
+ case 63: /* 22nm Haswell Server */
+ case 69: /* 22nm Haswell ULT */
+ case 70: /* 22nm Haswell + GT3e (Intel Iris Pro graphics) */
+
+ case 61: /* 14nm Broadwell Core-M */
+ case 86: /* 14nm Broadwell Xeon D */
+ case 71: /* 14nm Broadwell + GT3e (Intel Iris Pro graphics) */
+ case 79: /* 14nm Broadwell Server */
+
+ case 55: /* 22nm Atom "Silvermont" */
+ case 77: /* 22nm Atom "Silvermont Avoton/Rangely" */
+ case 76: /* 14nm Atom "Airmont" */
+ if (idx == PERF_MSR_SMI)
+ return true;
+ break;
+
+ case 78: /* 14nm Skylake Mobile */
+ case 94: /* 14nm Skylake Desktop */
+ if (idx == PERF_MSR_SMI || idx = PERF_MSR_PPERF)
+ return true;
+ break;
+ }
+
+ return false;
+}
+
struct perf_msr {
- int id;
u64 msr;
-};
-
-static struct perf_msr msr[] = {
- { PERF_MSR_TSC, 0 },
- { PERF_MSR_APERF, MSR_IA32_APERF },
- { PERF_MSR_MPERF, MSR_IA32_MPERF },
- { PERF_MSR_PPERF, MSR_PPERF },
- { PERF_MSR_SMI, MSR_SMI_COUNT },
+ struct perf_pmu_events_attr *attr;
+ bool (*test)(int idx);
};
PMU_EVENT_ATTR_STRING(tsc, evattr_tsc, "event=0x00");
@@ -29,8 +75,16 @@ PMU_EVENT_ATTR_STRING(mperf, evattr_mper
PMU_EVENT_ATTR_STRING(pperf, evattr_pperf, "event=0x03");
PMU_EVENT_ATTR_STRING(smi, evattr_smi, "event=0x04");
+static struct perf_msr msr[] = {
+ [PERF_MSR_TSC] = { 0, &evattr_tsc, NULL, },
+ [PERF_MSR_APERF] = { MSR_IA32_APERF, &evattr_aperf, test_aperfmperf, },
+ [PERF_MSR_MPERF] = { MSR_IA32_MPERF, &evattr_mperf, test_aperfmperf, },
+ [PERF_MSR_PPERF] = { MSR_PPERF, &evattr_pperf, test_intel, },
+ [PERF_MSR_SMI] = { MSR_SMI_COUNT, &evattr_smi, test_intel, },
+};
+
static struct attribute *events_attrs[PERF_MSR_EVENT_MAX + 1] = {
- &evattr_tsc.attr.attr,
+ NULL,
};
static struct attribute_group events_attr_group = {
@@ -74,6 +128,9 @@ static int msr_event_init(struct perf_ev
event->attr.sample_period) /* no sampling */
return -EINVAL;
+ if (!msr[cfg].attr)
+ return -EINVAL;
+
event->hw.idx = -1;
event->hw.event_base = msr[cfg].msr;
event->hw.config = cfg;
@@ -151,89 +208,32 @@ static struct pmu pmu_msr = {
.capabilities = PERF_PMU_CAP_NO_INTERRUPT,
};
-static int __init intel_msr_init(int idx)
-{
- if (boot_cpu_data.x86 != 6)
- return 0;
-
- switch (boot_cpu_data.x86_model) {
- case 30: /* 45nm Nehalem */
- case 26: /* 45nm Nehalem-EP */
- case 46: /* 45nm Nehalem-EX */
-
- case 37: /* 32nm Westmere */
- case 44: /* 32nm Westmere-EP */
- case 47: /* 32nm Westmere-EX */
-
- case 42: /* 32nm SandyBridge */
- case 45: /* 32nm SandyBridge-E/EN/EP */
-
- case 58: /* 22nm IvyBridge */
- case 62: /* 22nm IvyBridge-EP/EX */
-
- case 60: /* 22nm Haswell Core */
- case 63: /* 22nm Haswell Server */
- case 69: /* 22nm Haswell ULT */
- case 70: /* 22nm Haswell + GT3e (Intel Iris Pro graphics) */
-
- case 61: /* 14nm Broadwell Core-M */
- case 86: /* 14nm Broadwell Xeon D */
- case 71: /* 14nm Broadwell + GT3e (Intel Iris Pro graphics) */
- case 79: /* 14nm Broadwell Server */
- events_attrs[idx++] = &evattr_smi.attr.attr;
- break;
-
- case 78: /* 14nm Skylake Mobile */
- case 94: /* 14nm Skylake Desktop */
- events_attrs[idx++] = &evattr_pperf.attr.attr;
- events_attrs[idx++] = &evattr_smi.attr.attr;
- break;
-
- case 55: /* 22nm Atom "Silvermont" */
- case 76: /* 14nm Atom "Airmont" */
- case 77: /* 22nm Atom "Silvermont Avoton/Rangely" */
- events_attrs[idx++] = &evattr_smi.attr.attr;
- break;
- }
-
- events_attrs[idx] = NULL;
-
- return 0;
-}
-
-static int __init amd_msr_init(int idx)
-{
- return 0;
-}
-
static int __init msr_init(void)
{
- int err;
- int idx = 1;
+ int i, j = 0;
- if (boot_cpu_has(X86_FEATURE_APERFMPERF)) {
- events_attrs[idx++] = &evattr_aperf.attr.attr;
- events_attrs[idx++] = &evattr_mperf.attr.attr;
- events_attrs[idx] = NULL;
+ if (!boot_cpu_has(X86_FEATURE_TSC)) {
+ pr_cont("no MSR PMU driver.\n");
+ return 0;
}
- switch (boot_cpu_data.x86_vendor) {
- case X86_VENDOR_INTEL:
- err = intel_msr_init(idx);
- break;
-
- case X86_VENDOR_AMD:
- err = amd_msr_init(idx);
- break;
-
- default:
- err = -ENOTSUPP;
+ /* Probe the MSRs. */
+ for (i = PERF_MSR_TSC + 1; i < PERF_MSR_EVENT_MAX; i++) {
+ u64 val;
+
+ /*
+ * Virt sucks arse; you cannot tell if a R/O MSR is present :/
+ */
+ if (!msr[i].test(i) || rdmsrl_safe(msr[i].msr, &val))
+ msr[i].attr = NULL;
}
- if (err != 0) {
- pr_cont("no msr PMU driver.\n");
- return 0;
+ /* List remaining MSRs in the sysfs attrs. */
+ for (i = 0; i < PERF_MSR_EVENT_MAX; i++) {
+ if (msr[i].attr)
+ events_attrs[j++] = &msr[i].attr->attr.attr;
}
+ events_attrs[j] = NULL;
perf_pmu_register(&pmu_msr, "msr", -1);
--
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