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cxl/region: Add sysfs attribute for locality attributes of CXL regions 

Add read/write latencies and bandwidth sysfs attributes for the enabled CXL
region. The bandwidth is the aggregated bandwidth of all devices that
contribute to the CXL region. The latency is the worst latency of the
device amongst all the devices that contribute to the CXL region.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20240308220055.2172956-11-dave.jiang@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dave Jiang 2024-03-08 14:59:29 -07:00 committed by Dan Williams
parent 3d9f4a1972
commit c20eaf4411
2 changed files with 128 additions and 0 deletions
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34
Documentation/ABI/testing/sysfs-bus-cxl
View File

@ -552,3 +552,37 @@ Description:
attribute is only visible for devices supporting the
capability. The retrieved errors are logged as kernel
events when cxl_poison event tracing is enabled.
What: /sys/bus/cxl/devices/regionZ/accessY/read_bandwidth
/sys/bus/cxl/devices/regionZ/accessY/write_banwidth
Date: Jan, 2024
KernelVersion: v6.9
Contact: linux-cxl@vger.kernel.org
Description:
(RO) The aggregated read or write bandwidth of the region. The
number is the accumulated read or write bandwidth of all CXL memory
devices that contributes to the region in MB/s. It is
identical data that should appear in
/sys/devices/system/node/nodeX/accessY/initiators/read_bandwidth or
/sys/devices/system/node/nodeX/accessY/initiators/write_bandwidth.
See Documentation/ABI/stable/sysfs-devices-node. access0 provides
the number to the closest initiator and access1 provides the
number to the closest CPU.
What: /sys/bus/cxl/devices/regionZ/accessY/read_latency
/sys/bus/cxl/devices/regionZ/accessY/write_latency
Date: Jan, 2024
KernelVersion: v6.9
Contact: linux-cxl@vger.kernel.org
Description:
(RO) The read or write latency of the region. The number is
the worst read or write latency of all CXL memory devices that
contributes to the region in nanoseconds. It is identical data
that should appear in
/sys/devices/system/node/nodeX/accessY/initiators/read_latency or
/sys/devices/system/node/nodeX/accessY/initiators/write_latency.
See Documentation/ABI/stable/sysfs-devices-node. access0 provides
the number to the closest initiator and access1 provides the
number to the closest CPU.

94
drivers/cxl/core/region.c
View File

@ -30,6 +30,98 @@
static struct cxl_region *to_cxl_region(struct device *dev);
#define __ACCESS_ATTR_RO(_level, _name) { \
.attr = { .name = __stringify(_name), .mode = 0444 }, \
.show = _name##_access##_level##_show, \
}
#define ACCESS_DEVICE_ATTR_RO(level, name) \
struct device_attribute dev_attr_access##level##_##name = __ACCESS_ATTR_RO(level, name)
#define ACCESS_ATTR_RO(level, attrib) \
static ssize_t attrib##_access##level##_show(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct cxl_region *cxlr = to_cxl_region(dev); \
\
if (cxlr->coord[level].attrib == 0) \
return -ENOENT; \
\
return sysfs_emit(buf, "%u\n", cxlr->coord[level].attrib); \
} \
static ACCESS_DEVICE_ATTR_RO(level, attrib)
ACCESS_ATTR_RO(0, read_bandwidth);
ACCESS_ATTR_RO(0, read_latency);
ACCESS_ATTR_RO(0, write_bandwidth);
ACCESS_ATTR_RO(0, write_latency);
#define ACCESS_ATTR_DECLARE(level, attrib) \
(&dev_attr_access##level##_##attrib.attr)
static struct attribute *access0_coordinate_attrs[] = {
ACCESS_ATTR_DECLARE(0, read_bandwidth),
ACCESS_ATTR_DECLARE(0, write_bandwidth),
ACCESS_ATTR_DECLARE(0, read_latency),
ACCESS_ATTR_DECLARE(0, write_latency),
NULL
};
ACCESS_ATTR_RO(1, read_bandwidth);
ACCESS_ATTR_RO(1, read_latency);
ACCESS_ATTR_RO(1, write_bandwidth);
ACCESS_ATTR_RO(1, write_latency);
static struct attribute *access1_coordinate_attrs[] = {
ACCESS_ATTR_DECLARE(1, read_bandwidth),
ACCESS_ATTR_DECLARE(1, write_bandwidth),
ACCESS_ATTR_DECLARE(1, read_latency),
ACCESS_ATTR_DECLARE(1, write_latency),
NULL
};
#define ACCESS_VISIBLE(level) \
static umode_t cxl_region_access##level##_coordinate_visible( \
struct kobject *kobj, struct attribute *a, int n) \
{ \
struct device *dev = kobj_to_dev(kobj); \
struct cxl_region *cxlr = to_cxl_region(dev); \
\
if (a == &dev_attr_access##level##_read_latency.attr && \
cxlr->coord[level].read_latency == 0) \
return 0; \
\
if (a == &dev_attr_access##level##_write_latency.attr && \
cxlr->coord[level].write_latency == 0) \
return 0; \
\
if (a == &dev_attr_access##level##_read_bandwidth.attr && \
cxlr->coord[level].read_bandwidth == 0) \
return 0; \
\
if (a == &dev_attr_access##level##_write_bandwidth.attr && \
cxlr->coord[level].write_bandwidth == 0) \
return 0; \
\
return a->mode; \
}
ACCESS_VISIBLE(0);
ACCESS_VISIBLE(1);
static const struct attribute_group cxl_region_access0_coordinate_group = {
.name = "access0",
.attrs = access0_coordinate_attrs,
.is_visible = cxl_region_access0_coordinate_visible,
};
static const struct attribute_group cxl_region_access1_coordinate_group = {
.name = "access1",
.attrs = access1_coordinate_attrs,
.is_visible = cxl_region_access1_coordinate_visible,
};
static ssize_t uuid_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
@ -2069,6 +2161,8 @@ static const struct attribute_group *region_groups[] = {
&cxl_base_attribute_group,
&cxl_region_group,
&cxl_region_target_group,
&cxl_region_access0_coordinate_group,
&cxl_region_access1_coordinate_group,
NULL,
};