| Message ID | 1417799948-48440-1-git-send-email-d-gerlach@ti.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On Friday, December 05, 2014 11:19:08 AM Dave Gerlach wrote: > From: Nishanth Menon <nm@ti.com> > > PM QoS requests are notoriously hard to debug and made even > more so due to their highly dynamic nature. Having visibility > into the internal data representation per constraint allows > us to have much better appreciation of potential issues or > bad usage by drivers in the system. > > So introduce for all classes of PM QoS, an entry in > /sys/kernel/debug/pm_qos that shall show all the current > requests as well as the snapshot of the value these requests > boil down to. For example: > ==> /sys/kernel/debug/pm_qos/cpu_dma_latency <== > 1: 4444: Active > 2: 2000000000: Default > 3: 2000000000: Default > 4: 2000000000: Default > Type=Minimum, Value=4444, Requests: active=1 / total=4 > > ==> /sys/kernel/debug/pm_qos/memory_bandwidth <== > Empty! > > ... > > The actual value listed will have their meaning based > on the QoS it is on, the 'Type' indicates what logic > it would use to collate the information - Minimum, > Maximum, or Sum. Value is the collation of all requests. > This interface also compares the values with the defaults > for the QoS class and marks the ones that are > currently active. > > Signed-off-by: Nishanth Menon <nm@ti.com> > Signed-off-by: Dave Gerlach <d-gerlach@ti.com> This is fine by me, but let's wait and see if there are any comments. > --- > kernel/power/qos.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 89 insertions(+), 2 deletions(-) > > diff --git a/kernel/power/qos.c b/kernel/power/qos.c > index 5f4c006..97b0df7 100644 > --- a/kernel/power/qos.c > +++ b/kernel/power/qos.c > @@ -41,6 +41,8 @@ > #include <linux/platform_device.h> > #include <linux/init.h> > #include <linux/kernel.h> > +#include <linux/debugfs.h> > +#include <linux/seq_file.h> > > #include <linux/uaccess.h> > #include <linux/export.h> > @@ -182,6 +184,81 @@ static inline void pm_qos_set_value(struct pm_qos_constraints *c, s32 value) > c->target_value = value; > } > > +static inline int pm_qos_get_value(struct pm_qos_constraints *c); > +static int pm_qos_dbg_show_requests(struct seq_file *s, void *unused) > +{ > + struct pm_qos_object *qos = (struct pm_qos_object *)s->private; > + struct pm_qos_constraints *c; > + struct pm_qos_request *req; > + char *type; > + unsigned long flags; > + int tot_reqs = 0; > + int active_reqs = 0; > + > + if (IS_ERR_OR_NULL(qos)) { > + pr_err("%s: bad qos param!\n", __func__); > + return -EINVAL; > + } > + c = qos->constraints; > + if (IS_ERR_OR_NULL(c)) { > + pr_err("%s: Bad constraints on qos?\n", __func__); > + return -EINVAL; > + } > + > + /* Lock to ensure we have a snapshot */ > + spin_lock_irqsave(&pm_qos_lock, flags); > + if (plist_head_empty(&c->list)) { > + seq_puts(s, "Empty!\n"); > + goto out; > + } > + > + switch (c->type) { > + case PM_QOS_MIN: > + type = "Minimum"; > + break; > + case PM_QOS_MAX: > + type = "Maximum"; > + break; > + case PM_QOS_SUM: > + type = "Sum"; > + break; > + default: > + type = "Unknown"; > + } > + > + plist_for_each_entry(req, &c->list, node) { > + char *state = "Default"; > + > + if ((req->node).prio != c->default_value) { > + active_reqs++; > + state = "Active"; > + } > + tot_reqs++; > + seq_printf(s, "%d: %d: %s\n", tot_reqs, > + (req->node).prio, state); > + } > + > + seq_printf(s, "Type=%s, Value=%d, Requests: active=%d / total=%d\n", > + type, pm_qos_get_value(c), active_reqs, tot_reqs); > + > +out: > + spin_unlock_irqrestore(&pm_qos_lock, flags); > + return 0; > +} > + > +static int pm_qos_dbg_open(struct inode *inode, struct file *file) > +{ > + return single_open(file, pm_qos_dbg_show_requests, > + inode->i_private); > +} > + > +static const struct file_operations pm_qos_debug_fops = { > + .open = pm_qos_dbg_open, > + .read = seq_read, > + .llseek = seq_lseek, > + .release = single_release, > +}; > + > /** > * pm_qos_update_target - manages the constraints list and calls the notifiers > * if needed > @@ -509,12 +586,17 @@ int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier) > EXPORT_SYMBOL_GPL(pm_qos_remove_notifier); > > /* User space interface to PM QoS classes via misc devices */ > -static int register_pm_qos_misc(struct pm_qos_object *qos) > +static int register_pm_qos_misc(struct pm_qos_object *qos, struct dentry *d) > { > qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR; > qos->pm_qos_power_miscdev.name = qos->name; > qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops; > > + if (d) { > + (void)debugfs_create_file(qos->name, S_IRUGO, d, > + (void *)qos, &pm_qos_debug_fops); > + } > + > return misc_register(&qos->pm_qos_power_miscdev); > } > > @@ -608,11 +690,16 @@ static int __init pm_qos_power_init(void) > { > int ret = 0; > int i; > + struct dentry *d; > > BUILD_BUG_ON(ARRAY_SIZE(pm_qos_array) != PM_QOS_NUM_CLASSES); > > + d = debugfs_create_dir("pm_qos", NULL); > + if (IS_ERR_OR_NULL(d)) > + d = NULL; > + > for (i = PM_QOS_CPU_DMA_LATENCY; i < PM_QOS_NUM_CLASSES; i++) { > - ret = register_pm_qos_misc(pm_qos_array[i]); > + ret = register_pm_qos_misc(pm_qos_array[i], d); > if (ret < 0) { > printk(KERN_ERR "pm_qos_param: %s setup failed\n", > pm_qos_array[i]->name); >
Dave Gerlach <d-gerlach@ti.com> writes: > From: Nishanth Menon <nm@ti.com> > > PM QoS requests are notoriously hard to debug and made even > more so due to their highly dynamic nature. Having visibility > into the internal data representation per constraint allows > us to have much better appreciation of potential issues or > bad usage by drivers in the system. > > So introduce for all classes of PM QoS, an entry in > /sys/kernel/debug/pm_qos that shall show all the current > requests as well as the snapshot of the value these requests > boil down to. For example: > ==> /sys/kernel/debug/pm_qos/cpu_dma_latency <== > 1: 4444: Active > 2: 2000000000: Default > 3: 2000000000: Default > 4: 2000000000: Default > Type=Minimum, Value=4444, Requests: active=1 / total=4 > > ==> /sys/kernel/debug/pm_qos/memory_bandwidth <== > Empty! > > ... > > The actual value listed will have their meaning based > on the QoS it is on, the 'Type' indicates what logic > it would use to collate the information - Minimum, > Maximum, or Sum. Value is the collation of all requests. > This interface also compares the values with the defaults > for the QoS class and marks the ones that are > currently active. > > Signed-off-by: Nishanth Menon <nm@ti.com> > Signed-off-by: Dave Gerlach <d-gerlach@ti.com> A very useful feature indeed, Acked-by: Kevin Hilman <khilman@linaro.org> Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Monday, December 15, 2014 02:34:15 PM Kevin Hilman wrote: > Dave Gerlach <d-gerlach@ti.com> writes: > > > From: Nishanth Menon <nm@ti.com> > > > > PM QoS requests are notoriously hard to debug and made even > > more so due to their highly dynamic nature. Having visibility > > into the internal data representation per constraint allows > > us to have much better appreciation of potential issues or > > bad usage by drivers in the system. > > > > So introduce for all classes of PM QoS, an entry in > > /sys/kernel/debug/pm_qos that shall show all the current > > requests as well as the snapshot of the value these requests > > boil down to. For example: > > ==> /sys/kernel/debug/pm_qos/cpu_dma_latency <== > > 1: 4444: Active > > 2: 2000000000: Default > > 3: 2000000000: Default > > 4: 2000000000: Default > > Type=Minimum, Value=4444, Requests: active=1 / total=4 > > > > ==> /sys/kernel/debug/pm_qos/memory_bandwidth <== > > Empty! > > > > ... > > > > The actual value listed will have their meaning based > > on the QoS it is on, the 'Type' indicates what logic > > it would use to collate the information - Minimum, > > Maximum, or Sum. Value is the collation of all requests. > > This interface also compares the values with the defaults > > for the QoS class and marks the ones that are > > currently active. > > > > Signed-off-by: Nishanth Menon <nm@ti.com> > > Signed-off-by: Dave Gerlach <d-gerlach@ti.com> > > A very useful feature indeed, > > Acked-by: Kevin Hilman <khilman@linaro.org> Queued up for 3.20, thanks!
diff --git a/kernel/power/qos.c b/kernel/power/qos.c index 5f4c006..97b0df7 100644 --- a/kernel/power/qos.c +++ b/kernel/power/qos.c @@ -41,6 +41,8 @@ #include <linux/platform_device.h> #include <linux/init.h> #include <linux/kernel.h> +#include <linux/debugfs.h> +#include <linux/seq_file.h> #include <linux/uaccess.h> #include <linux/export.h> @@ -182,6 +184,81 @@ static inline void pm_qos_set_value(struct pm_qos_constraints *c, s32 value) c->target_value = value; } +static inline int pm_qos_get_value(struct pm_qos_constraints *c); +static int pm_qos_dbg_show_requests(struct seq_file *s, void *unused) +{ + struct pm_qos_object *qos = (struct pm_qos_object *)s->private; + struct pm_qos_constraints *c; + struct pm_qos_request *req; + char *type; + unsigned long flags; + int tot_reqs = 0; + int active_reqs = 0; + + if (IS_ERR_OR_NULL(qos)) { + pr_err("%s: bad qos param!\n", __func__); + return -EINVAL; + } + c = qos->constraints; + if (IS_ERR_OR_NULL(c)) { + pr_err("%s: Bad constraints on qos?\n", __func__); + return -EINVAL; + } + + /* Lock to ensure we have a snapshot */ + spin_lock_irqsave(&pm_qos_lock, flags); + if (plist_head_empty(&c->list)) { + seq_puts(s, "Empty!\n"); + goto out; + } + + switch (c->type) { + case PM_QOS_MIN: + type = "Minimum"; + break; + case PM_QOS_MAX: + type = "Maximum"; + break; + case PM_QOS_SUM: + type = "Sum"; + break; + default: + type = "Unknown"; + } + + plist_for_each_entry(req, &c->list, node) { + char *state = "Default"; + + if ((req->node).prio != c->default_value) { + active_reqs++; + state = "Active"; + } + tot_reqs++; + seq_printf(s, "%d: %d: %s\n", tot_reqs, + (req->node).prio, state); + } + + seq_printf(s, "Type=%s, Value=%d, Requests: active=%d / total=%d\n", + type, pm_qos_get_value(c), active_reqs, tot_reqs); + +out: + spin_unlock_irqrestore(&pm_qos_lock, flags); + return 0; +} + +static int pm_qos_dbg_open(struct inode *inode, struct file *file) +{ + return single_open(file, pm_qos_dbg_show_requests, + inode->i_private); +} + +static const struct file_operations pm_qos_debug_fops = { + .open = pm_qos_dbg_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + /** * pm_qos_update_target - manages the constraints list and calls the notifiers * if needed @@ -509,12 +586,17 @@ int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier) EXPORT_SYMBOL_GPL(pm_qos_remove_notifier); /* User space interface to PM QoS classes via misc devices */ -static int register_pm_qos_misc(struct pm_qos_object *qos) +static int register_pm_qos_misc(struct pm_qos_object *qos, struct dentry *d) { qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR; qos->pm_qos_power_miscdev.name = qos->name; qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops; + if (d) { + (void)debugfs_create_file(qos->name, S_IRUGO, d, + (void *)qos, &pm_qos_debug_fops); + } + return misc_register(&qos->pm_qos_power_miscdev); } @@ -608,11 +690,16 @@ static int __init pm_qos_power_init(void) { int ret = 0; int i; + struct dentry *d; BUILD_BUG_ON(ARRAY_SIZE(pm_qos_array) != PM_QOS_NUM_CLASSES); + d = debugfs_create_dir("pm_qos", NULL); + if (IS_ERR_OR_NULL(d)) + d = NULL; + for (i = PM_QOS_CPU_DMA_LATENCY; i < PM_QOS_NUM_CLASSES; i++) { - ret = register_pm_qos_misc(pm_qos_array[i]); + ret = register_pm_qos_misc(pm_qos_array[i], d); if (ret < 0) { printk(KERN_ERR "pm_qos_param: %s setup failed\n", pm_qos_array[i]->name);