[PATCH 1/5] powerpc/hv-gpci: Fix starting index value

[PATCH 1/5] powerpc/hv-gpci: Fix starting index value

[Kajol Jain]

Commit 9e9f60108423f ("powerpc/perf/{hv-gpci, hv-common}: generate
requests with counters annotated") adds a framework for defining
gpci counters.
In this patch, they adds starting_index value as '0xffffffffffffffff'.
which is wrong as starting_index is of size 32 bits.

Because of this, incase we try to run hv-gpci event we get error.

In power9 machine:

command#: perf stat -e hv_gpci/system_tlbie_count_and_time_tlbie_instructions_issued/
          -C 0 -I 1000
event syntax error: '..bie_count_and_time_tlbie_instructions_issued/'
                                  \___ value too big for format, maximum is 4294967295

This patch fix this issue and changes starting_index value to '0xffffffff'

After this patch:

command#: perf stat -e hv_gpci/system_tlbie_count_and_time_tlbie_instructions_issued/ -C 0 -I 1000
     1.000085786              1,024      hv_gpci/system_tlbie_count_and_time_tlbie_instructions_issued/
     2.000287818              1,024      hv_gpci/system_tlbie_count_and_time_tlbie_instructions_issued/
^C     2.439113909             17,408      hv_gpci/system_tlbie_count_and_time_tlbie_instructions_issued/

Fixes: 9e9f60108423f ("powerpc/perf/{hv-gpci, hv-common}: generate
requests with counters annotated")
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 arch/powerpc/perf/hv-gpci-requests.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/perf/hv-gpci-requests.h b/arch/powerpc/perf/hv-gpci-requests.h
index e608f9db12dd..8965b4463d43 100644
--- a/arch/powerpc/perf/hv-gpci-requests.h
+++ b/arch/powerpc/perf/hv-gpci-requests.h
@@ -95,7 +95,7 @@ REQUEST(__field(0,	8,	partition_id)
 
 #define REQUEST_NAME system_performance_capabilities
 #define REQUEST_NUM 0x40
-#define REQUEST_IDX_KIND "starting_index=0xffffffffffffffff"
+#define REQUEST_IDX_KIND "starting_index=0xffffffff"
 #include I(REQUEST_BEGIN)
 REQUEST(__field(0,	1,	perf_collect_privileged)
 	__field(0x1,	1,	capability_mask)
@@ -223,7 +223,7 @@ REQUEST(__field(0,	2, partition_id)
 
 #define REQUEST_NAME system_hypervisor_times
 #define REQUEST_NUM 0xF0
-#define REQUEST_IDX_KIND "starting_index=0xffffffffffffffff"
+#define REQUEST_IDX_KIND "starting_index=0xffffffff"
 #include I(REQUEST_BEGIN)
 REQUEST(__count(0,	8,	time_spent_to_dispatch_virtual_processors)
 	__count(0x8,	8,	time_spent_processing_virtual_processor_timers)
@@ -234,7 +234,7 @@ REQUEST(__count(0,	8,	time_spent_to_dispatch_virtual_processors)
 
 #define REQUEST_NAME system_tlbie_count_and_time
 #define REQUEST_NUM 0xF4
-#define REQUEST_IDX_KIND "starting_index=0xffffffffffffffff"
+#define REQUEST_IDX_KIND "starting_index=0xffffffff"
 #include I(REQUEST_BEGIN)
 REQUEST(__count(0,	8,	tlbie_instructions_issued)
 	/*
-- 
2.26.2

[PATCH 2/5] Documentation/ABI: Add ABI documentation for hv-24x7 format

[Kajol Jain]

This patch adds ABI documentation for hv-24x7 format.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 .../sysfs-bus-event_source-devices-hv_24x7    | 25 +++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_24x7 b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_24x7
index e82fc37be802..6bec9a13a493 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_24x7
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_24x7
@@ -1,3 +1,28 @@
+What:           /sys/bus/event_source/devices/hv_24x7/format
+Date:           September 2020
+Contact:        Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
+Description:    Read-only. Attribute group to describe the magic bits
+                that go into perf_event_attr.config for a particular pmu.
+                (See ABI/testing/sysfs-bus-event_source-devices-format).
+
+                Each attribute under this group defines a bit range of the
+                perf_event_attr.config. All supported attributes are listed
+                below.
+
+				chip = "config:16-31"
+				core  = "config:16-31"
+				domain = "config:0-3"
+				lpar = "config:0-15"
+				offset = "config:32-63"
+				vcpu = "config:16-31"
+
+               For example,
+
+		PM_PB_CYC =  "domain=1,offset=0x80,chip=?,lpar=0x0"
+
+		In this event, '?' after chip specifies that
+		this value will be provided by user while running this event.
+
 What:		/sys/bus/event_source/devices/hv_24x7/interface/catalog
 Date:		February 2014
 Contact:	Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
-- 
2.26.2

[PATCH 3/5] Documentation/ABI: Add ABI documentation for hv-gpci format

[Kajol Jain]

This patch adds ABI documentation for hv-gpci event format.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 .../sysfs-bus-event_source-devices-hv_gpci    | 31 +++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
index 3ca4e554d2f9..b68a28a712d5 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
@@ -1,3 +1,34 @@
+What:           /sys/bus/event_source/devices/hv_gpci/format
+Date:           September 2020
+Contact:        Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
+Description:    Read-only. Attribute group to describe the magic bits
+                that go into perf_event_attr.config for a particular pmu.
+                (See ABI/testing/sysfs-bus-event_source-devices-format).
+
+                Each attribute under this group defines a bit range of the
+                perf_event_attr.config. All supported attributes are listed
+                below.
+
+				counter_info_version  = "config:16-23"
+				length  = "config:24-31"
+				partition_id  = "config:32-63"
+				request = "config:0-31"
+				sibling_part_id = "config:32-63"
+				hw_chip_id = "config:32-63"
+				offset = "config:32-63"
+				phys_processor_idx = "config:32-63"
+				secondary_index = "config:0-15"
+				starting_index = "config:32-63"
+
+               For example,
+
+		processor_core_utilization_instructions_completed = "request=0x94,
+					phys_processor_idx=?,counter_info_version=0x8,
+					length=8,offset=0x18"
+
+		In this event, '?' after phys_processor_idx specifies this value
+		this value will be provided by user while running this event.
+
 What:		/sys/bus/event_source/devices/hv_gpci/interface/collect_privileged
 Date:		February 2014
 Contact:	Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
-- 
2.26.2

[PATCH 4/5] powerpc/perf/hv-gpci: Add cpu hotplug support

[Kajol Jain]

Patch here adds cpu hotplug functions to hv_gpci pmu.
A new cpuhp_state "CPUHP_AP_PERF_POWERPC_HV_GPCI_ONLINE" enum
is added.

The online callback function updates the cpumask only if its
empty. As the primary intention of adding hotplug support
is to designate a CPU to make HCALL to collect the
counter data.

The offline function test and clear corresponding cpu in a cpumask
and update cpumask to any other active cpu.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 arch/powerpc/perf/hv-gpci.c | 46 +++++++++++++++++++++++++++++++++++++
 include/linux/cpuhotplug.h  |  1 +
 2 files changed, 47 insertions(+)

diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index 6884d16ec19b..b9dc407c3159 100644
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -48,6 +48,8 @@ EVENT_DEFINE_RANGE_FORMAT(length, config1, 24, 31);
 /* u32, byte offset */
 EVENT_DEFINE_RANGE_FORMAT(offset, config1, 32, 63);
 
+static cpumask_t hv_gpci_cpumask;
+
 static struct attribute *format_attrs[] = {
 	&format_attr_request.attr,
 	&format_attr_starting_index.attr,
@@ -275,6 +277,45 @@ static struct pmu h_gpci_pmu = {
 	.capabilities = PERF_PMU_CAP_NO_EXCLUDE,
 };
 
+static int ppc_hv_gpci_cpu_online(unsigned int cpu)
+{
+	if (cpumask_empty(&hv_gpci_cpumask))
+		cpumask_set_cpu(cpu, &hv_gpci_cpumask);
+
+	return 0;
+}
+
+static int ppc_hv_gpci_cpu_offline(unsigned int cpu)
+{
+	int target;
+
+	/* Check if exiting cpu is used for collecting gpci events */
+	if (!cpumask_test_and_clear_cpu(cpu, &hv_gpci_cpumask))
+		return 0;
+
+	/* Find a new cpu to collect gpci events */
+	target = cpumask_last(cpu_active_mask);
+
+	if (target < 0 || target >= nr_cpu_ids) {
+		pr_err("hv_gpci: CPU hotplug init failed\n");
+		return -1;
+	}
+
+	/* Migrate gpci events to the new target */
+	cpumask_set_cpu(target, &hv_gpci_cpumask);
+	perf_pmu_migrate_context(&h_gpci_pmu, cpu, target);
+
+	return 0;
+}
+
+static int hv_gpci_cpu_hotplug_init(void)
+{
+	return cpuhp_setup_state(CPUHP_AP_PERF_POWERPC_HV_GPCI_ONLINE,
+			  "perf/powerpc/hv_gcpi:online",
+			  ppc_hv_gpci_cpu_online,
+			  ppc_hv_gpci_cpu_offline);
+}
+
 static int hv_gpci_init(void)
 {
 	int r;
@@ -295,6 +336,11 @@ static int hv_gpci_init(void)
 		return -ENODEV;
 	}
 
+	/* init cpuhotplug */
+	r = hv_gpci_cpu_hotplug_init();
+	if (r)
+		return r;
+
 	/* sampling not supported */
 	h_gpci_pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
 
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index bf9181cef444..b79d3d4b06e8 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -182,6 +182,7 @@ enum cpuhp_state {
 	CPUHP_AP_PERF_POWERPC_THREAD_IMC_ONLINE,
 	CPUHP_AP_PERF_POWERPC_TRACE_IMC_ONLINE,
 	CPUHP_AP_PERF_POWERPC_HV_24x7_ONLINE,
+	CPUHP_AP_PERF_POWERPC_HV_GPCI_ONLINE,
 	CPUHP_AP_WATCHDOG_ONLINE,
 	CPUHP_AP_WORKQUEUE_ONLINE,
 	CPUHP_AP_RCUTREE_ONLINE,
-- 
2.26.2

[PATCH 5/5] powerpc/hv-gpci: Add sysfs files inside hv-gpci device to show cpumask

[Kajol Jain]

Patch here adds a cpumask attr to hv_gpci pmu along with ABI documentation.

Primary use to expose the cpumask is for the perf tool which has the
capability to parse the driver sysfs folder and understand the
cpumask file. Having cpumask file will reduce the number of perf command
line parameters (will avoid "-C" option in the perf tool
command line). It can also notify the user which is
the current cpu used to retrieve the counter data.

command:# cat /sys/devices/hv_gpci/cpumask
0

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 .../sysfs-bus-event_source-devices-hv_gpci     |  7 +++++++
 arch/powerpc/perf/hv-gpci.c                    | 18 ++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
index b68a28a712d5..7162c5d675fe 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
@@ -72,3 +72,10 @@ Contact:	Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
 Description:
 		A number indicating the latest version of the gpci interface
 		that the kernel is aware of.
+
+What:		/sys/devices/hv_gpci/cpumask
+Date:		October 2020
+Contact:	Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
+Description:	read only
+		This sysfs file exposes the cpumask which is designated to make
+		HCALLs to retrieve hv-gpci pmu event counter data.
diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index b9dc407c3159..159dca8d5d65 100644
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -96,7 +96,15 @@ static ssize_t kernel_version_show(struct device *dev,
 	return sprintf(page, "0x%x\n", COUNTER_INFO_VERSION_CURRENT);
 }
 
+static ssize_t cpumask_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	return cpumap_print_to_pagebuf(true, buf, &hv_gpci_cpumask);
+}
+
 static DEVICE_ATTR_RO(kernel_version);
+static DEVICE_ATTR_RO(cpumask);
+
 HV_CAPS_ATTR(version, "0x%x\n");
 HV_CAPS_ATTR(ga, "%d\n");
 HV_CAPS_ATTR(expanded, "%d\n");
@@ -113,6 +121,15 @@ static struct attribute *interface_attrs[] = {
 	NULL,
 };
 
+static struct attribute *cpumask_attrs[] = {
+	&dev_attr_cpumask.attr,
+	NULL,
+};
+
+static struct attribute_group cpumask_attr_group = {
+	.attrs = cpumask_attrs,
+};
+
 static struct attribute_group interface_group = {
 	.name = "interface",
 	.attrs = interface_attrs,
@@ -122,6 +139,7 @@ static const struct attribute_group *attr_groups[] = {
 	&format_group,
 	&event_group,
 	&interface_group,
+	&cpumask_attr_group,
 	NULL,
 };
 
-- 
2.26.2

Re: [PATCH 1/5] powerpc/hv-gpci: Fix starting index value

[Michael Ellerman]

On Sat, 3 Oct 2020 13:19:39 +0530, Kajol Jain wrote:
> Commit 9e9f60108423f ("powerpc/perf/{hv-gpci, hv-common}: generate
> requests with counters annotated") adds a framework for defining
> gpci counters.
> In this patch, they adds starting_index value as '0xffffffffffffffff'.
> which is wrong as starting_index is of size 32 bits.
> 
> Because of this, incase we try to run hv-gpci event we get error.
> 
> [...]

Applied to powerpc/next.

[1/5] powerpc/perf/hv-gpci: Fix starting index value
      https://git.kernel.org/powerpc/c/0f9866f7e85765bbda86666df56c92f377c3bc10
[2/5] Documentation/ABI: Add ABI documentation for hv-24x7 format
      https://git.kernel.org/powerpc/c/264a034099b6e3c76fae85e75329373f3652a033
[3/5] Documentation/ABI: Add ABI documentation for hv-gpci format
      https://git.kernel.org/powerpc/c/435387dd1f6fc03c64e3fdb4cc8737904c08a4db
[4/5] powerpc/perf/hv-gpci: Add cpu hotplug support
      https://git.kernel.org/powerpc/c/dcb5cdf60a1fbbdb3b4dd2abc562206481f09ef1
[5/5] powerpc/hv-gpci: Add sysfs files inside hv-gpci device to show cpumask
      https://git.kernel.org/powerpc/c/09b791d95559ef82542063333ecaa2ac9d57118e

cheers