Attachment 120068 Details for Bug 93035 – Patch to enable AHCI ALPM accounting

[patch] Patch to enable AHCI ALPM accounting

0001-Updated-PowerTOP-AHCI-ALPM-accounting-for-Device-Sle.patch (text/plain), 11.14 KB, created by Imre Deak on 2015-11-23 19:33:20 UTC

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Creator: Imre Deak

Created: 2015-11-23 19:33:20 UTC

Size: 11.14 KB

patch

obsolete

>From af09f2593c8b46b16d95e0f864182eb6b7007fc9 Mon Sep 17 00:00:00 2001
>From: David Woodhouse <dwmw2@infradead.org>
>Date: Mon, 1 Apr 2013 20:53:07 +0100
>Subject: [PATCH] Updated PowerTOP AHCI ALPM accounting for Device Sleep.
>
>This is an out of tree patch, retrieved from the powertop upstream
>git tree.  It has been carried out of tree for over 5 years now.
>It isn't on a path to upstream because the maintainers objected
>to where the statistics were being tracked in sysfs.  A JIRA is
>filed to track progress towards upstream, but as it is a P2 item
>and hasn't been updated *ever*, I suspect that it isn't going anywhere.
>It also has a corner case in which it may not be accurate
>
>https://jira01.devtools.intel.com/browse/LCK-518
>
>Meanwhile, this patch is used by powertop and other tools to
>gather SATA LPM statistics and is considered quite useful by our
>internal teams.
>
> --Kristen
>
>This patch applies to v3.7 onwards (including 3.9-rc4), and adds devslp
>support to the AHCI state accounting. It's based on the patch at
>https://raw.github.com/fenrus75/powertop/master/patches/linux-3.3.0-ahci-alpm-accounting.patch
>
>From: Arjan van de Ven <arjan@linux.intel.com>
>Subject: libata: Add ALPM power state accounting to the AHCI driver
>
>PowerTOP wants to be able to show the user how effective the ALPM link
>power management is for the user. ALPM is worth around 0.5W on a quiet
>link; PowerTOP wants to be able to find cases where the "quiet link" isn't
>actually quiet.
>
>This patch adds state accounting functionality to the AHCI driver for
>PowerTOP to use.
>The parts of the patch are
>1) the sysfs logic of exposing the stats for each state in sysfs
>2) the basic accounting logic that gets update on link change interrupts
>   (or when the user accesses the info from sysfs)
>3) a "accounting enable" flag; in order to get the accounting to work,
>   the driver needs to get phyrdy interrupts on link status changes.
>   Normally and currently this is disabled by the driver when ALPM is
>   on (to reduce overhead); when PowerTOP is running this will need
>   to be on to get usable statistics... hence the sysfs tunable.
>
>The PowerTOP output currently looks like this:
>
>Recent SATA AHCI link activity statistics
>Active	Partial	Slumber	Device name
>  0.5%	 99.5%	  0.0%	host0
>
>(work to resolve "host0" to a more human readable name is in progress)
>
>Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
>Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
>Signed-off-by: David E. Box <david.e.box@linux.intel.com>
>---
> drivers/ata/ahci.h    |  17 ++++
> drivers/ata/libahci.c | 211 +++++++++++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 226 insertions(+), 2 deletions(-)
>
>diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
>index 45586c1..3e30e4c 100644
>--- a/drivers/ata/ahci.h
>+++ b/drivers/ata/ahci.h
>@@ -296,6 +296,14 @@ struct ahci_em_priv {
> 	unsigned long led_state;
> };
> 
>+enum ahci_port_states {
>+	AHCI_PORT_NOLINK	= 0,
>+	AHCI_PORT_ACTIVE	= 1,
>+	AHCI_PORT_PARTIAL	= 2,
>+	AHCI_PORT_SLUMBER	= 3,
>+	AHCI_PORT_DEVSLP	= 4
>+};
>+
> struct ahci_port_priv {
> 	struct ata_link		*active_link;
> 	struct ahci_cmd_hdr	*cmd_slot;
>@@ -317,6 +325,15 @@ struct ahci_port_priv {
> 	/* enclosure management info per PM slot */
> 	struct ahci_em_priv	em_priv[EM_MAX_SLOTS];
> 	char			*irq_desc;	/* desc in /proc/interrupts */
>+
>+	/* ALPM accounting state and stats */
>+	unsigned int		accounting_active:1;
>+	u64			active_jiffies;
>+	u64			partial_jiffies;
>+	u64			slumber_jiffies;
>+	u64			devslp_jiffies;
>+	int			previous_state;
>+	int			previous_jiffies;
> };
> 
> struct ahci_host_priv {
>diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
>index 096064c..5739182 100644
>--- a/drivers/ata/libahci.c
>+++ b/drivers/ata/libahci.c
>@@ -97,6 +97,19 @@ static ssize_t ahci_activity_store(struct ata_device *dev,
> 				   enum sw_activity val);
> static void ahci_init_sw_activity(struct ata_link *link);
> 
>+static ssize_t ahci_alpm_show_active(struct device *dev,
>+				  struct device_attribute *attr, char *buf);
>+static ssize_t ahci_alpm_show_slumber(struct device *dev,
>+				  struct device_attribute *attr, char *buf);
>+static ssize_t ahci_alpm_show_devslp(struct device *dev,
>+				  struct device_attribute *attr, char *buf);
>+static ssize_t ahci_alpm_show_partial(struct device *dev,
>+				  struct device_attribute *attr, char *buf);
>+static ssize_t ahci_alpm_show_accounting(struct device *dev,
>+				  struct device_attribute *attr, char *buf);
>+static ssize_t ahci_alpm_set_accounting(struct device *dev,
>+				  struct device_attribute *attr,
>+				  const char *buf, size_t count);
> static ssize_t ahci_show_host_caps(struct device *dev,
> 				   struct device_attribute *attr, char *buf);
> static ssize_t ahci_show_host_cap2(struct device *dev,
>@@ -117,6 +130,13 @@ static DEVICE_ATTR(ahci_host_caps, S_IRUGO, ahci_show_host_caps, NULL);
> static DEVICE_ATTR(ahci_host_cap2, S_IRUGO, ahci_show_host_cap2, NULL);
> static DEVICE_ATTR(ahci_host_version, S_IRUGO, ahci_show_host_version, NULL);
> static DEVICE_ATTR(ahci_port_cmd, S_IRUGO, ahci_show_port_cmd, NULL);
>+static DEVICE_ATTR(ahci_alpm_active, S_IRUGO, ahci_alpm_show_active, NULL);
>+static DEVICE_ATTR(ahci_alpm_partial, S_IRUGO, ahci_alpm_show_partial, NULL);
>+static DEVICE_ATTR(ahci_alpm_slumber, S_IRUGO, ahci_alpm_show_slumber, NULL);
>+static DEVICE_ATTR(ahci_alpm_devslp, S_IRUGO, ahci_alpm_show_devslp, NULL);
>+static DEVICE_ATTR(ahci_alpm_accounting, S_IRUGO | S_IWUSR,
>+		ahci_alpm_show_accounting, ahci_alpm_set_accounting);
>+
> static DEVICE_ATTR(em_buffer, S_IWUSR | S_IRUGO,
> 		   ahci_read_em_buffer, ahci_store_em_buffer);
> static DEVICE_ATTR(em_message_supported, S_IRUGO, ahci_show_em_supported, NULL);
>@@ -129,6 +149,11 @@ struct device_attribute *ahci_shost_attrs[] = {
> 	&dev_attr_ahci_host_cap2,
> 	&dev_attr_ahci_host_version,
> 	&dev_attr_ahci_port_cmd,
>+	&dev_attr_ahci_alpm_active,
>+	&dev_attr_ahci_alpm_partial,
>+	&dev_attr_ahci_alpm_slumber,
>+	&dev_attr_ahci_alpm_devslp,
>+	&dev_attr_ahci_alpm_accounting,
> 	&dev_attr_em_buffer,
> 	&dev_attr_em_message_supported,
> 	NULL
>@@ -223,6 +248,182 @@ static void ahci_enable_ahci(void __iomem *mmio)
> 	WARN_ON(1);
> }
> 
>+static int get_current_alpm_state(struct ata_port *ap)
>+{
>+	u32 status = 0;
>+
>+	ahci_scr_read(&ap->link, SCR_STATUS, &status);
>+
>+	/* link status is in bits 11-8 */
>+	status = status >> 8;
>+	status = status & 0xf;
>+
>+	if (status == 8)
>+		return AHCI_PORT_DEVSLP;
>+	if (status == 6)
>+		return AHCI_PORT_SLUMBER;
>+	if (status == 2)
>+		return AHCI_PORT_PARTIAL;
>+	if (status == 1)
>+		return AHCI_PORT_ACTIVE;
>+	return AHCI_PORT_NOLINK;
>+}
>+
>+static void account_alpm_stats(struct ata_port *ap)
>+{
>+	struct ahci_port_priv *pp;
>+
>+	int new_state;
>+	u64 new_jiffies, jiffies_delta;
>+
>+	if (ap == NULL)
>+		return;
>+	pp = ap->private_data;
>+
>+	if (!pp) return;
>+
>+	new_state = get_current_alpm_state(ap);
>+	new_jiffies = jiffies;
>+
>+	jiffies_delta = new_jiffies - pp->previous_jiffies;
>+
>+	switch (pp->previous_state) {
>+	case AHCI_PORT_NOLINK:
>+		pp->active_jiffies = 0;
>+		pp->partial_jiffies = 0;
>+		pp->slumber_jiffies = 0;
>+		break;
>+	case AHCI_PORT_ACTIVE:
>+		pp->active_jiffies += jiffies_delta;
>+		break;
>+	case AHCI_PORT_PARTIAL:
>+		pp->partial_jiffies += jiffies_delta;
>+		break;
>+	case AHCI_PORT_SLUMBER:
>+		pp->slumber_jiffies += jiffies_delta;
>+		break;
>+	case AHCI_PORT_DEVSLP:
>+		pp->devslp_jiffies += jiffies_delta;
>+		break;
>+	default:
>+		break;
>+	}
>+	pp->previous_state = new_state;
>+	pp->previous_jiffies = new_jiffies;
>+}
>+
>+static ssize_t ahci_alpm_show_active(struct device *dev,
>+				   struct device_attribute *attr, char *buf)
>+{
>+	struct Scsi_Host *shost = class_to_shost(dev);
>+	struct ata_port *ap = ata_shost_to_port(shost);
>+	struct ahci_port_priv *pp;
>+
>+	if (!ap || ata_port_is_dummy(ap))
>+		return -EINVAL;
>+
>+	pp = ap->private_data;
>+	account_alpm_stats(ap);
>+
>+	return sprintf(buf, "%u\n", jiffies_to_msecs(pp->active_jiffies));
>+}
>+
>+static ssize_t ahci_alpm_show_partial(struct device *dev,
>+				   struct device_attribute *attr, char *buf)
>+{
>+	struct Scsi_Host *shost = class_to_shost(dev);
>+	struct ata_port *ap = ata_shost_to_port(shost);
>+	struct ahci_port_priv *pp;
>+
>+	if (!ap || ata_port_is_dummy(ap))
>+		return -EINVAL;
>+
>+	pp = ap->private_data;
>+	account_alpm_stats(ap);
>+
>+	return sprintf(buf, "%u\n", jiffies_to_msecs(pp->partial_jiffies));
>+}
>+
>+static ssize_t ahci_alpm_show_slumber(struct device *dev,
>+				   struct device_attribute *attr, char *buf)
>+{
>+	struct Scsi_Host *shost = class_to_shost(dev);
>+	struct ata_port *ap = ata_shost_to_port(shost);
>+	struct ahci_port_priv *pp;
>+
>+	if (!ap || ata_port_is_dummy(ap))
>+		return -EINVAL;
>+
>+	pp = ap->private_data;
>+	account_alpm_stats(ap);
>+
>+	return sprintf(buf, "%u\n", jiffies_to_msecs(pp->slumber_jiffies));
>+}
>+
>+static ssize_t ahci_alpm_show_devslp(struct device *dev,
>+				   struct device_attribute *attr, char *buf)
>+{
>+	struct Scsi_Host *shost = class_to_shost(dev);
>+	struct ata_port *ap = ata_shost_to_port(shost);
>+	struct ahci_port_priv *pp;
>+
>+	if (!ap || ata_port_is_dummy(ap))
>+		return -EINVAL;
>+
>+	pp = ap->private_data;
>+	account_alpm_stats(ap);
>+
>+	return sprintf(buf, "%u\n", jiffies_to_msecs(pp->devslp_jiffies));
>+}
>+
>+static ssize_t ahci_alpm_show_accounting(struct device *dev,
>+				  struct device_attribute *attr, char *buf)
>+{
>+	struct Scsi_Host *shost = class_to_shost(dev);
>+	struct ata_port *ap = ata_shost_to_port(shost);
>+	struct ahci_port_priv *pp;
>+
>+	if (!ap || ata_port_is_dummy(ap))
>+		return -EINVAL;
>+
>+	pp = ap->private_data;
>+
>+	return sprintf(buf, "%u\n", pp->accounting_active);
>+}
>+
>+static ssize_t ahci_alpm_set_accounting(struct device *dev,
>+				  struct device_attribute *attr,
>+				  const char *buf, size_t count)
>+{
>+	unsigned long flags;
>+	struct Scsi_Host *shost = class_to_shost(dev);
>+	struct ata_port *ap = ata_shost_to_port(shost);
>+	struct ahci_port_priv *pp;
>+	void __iomem *port_mmio;
>+
>+	if (!ap || ata_port_is_dummy(ap))
>+		return 1;
>+
>+	pp = ap->private_data;
>+	port_mmio = ahci_port_base(ap);
>+
>+	if (!pp)
>+		return 1;
>+	if (buf[0] == '0')
>+		pp->accounting_active = 0;
>+	if (buf[0] == '1')
>+		pp->accounting_active = 1;
>+
>+	/* we need to enable the PHYRDY interrupt when we want accounting */
>+	if (pp->accounting_active) {
>+		spin_lock_irqsave(ap->lock, flags);
>+		pp->intr_mask |= PORT_IRQ_PHYRDY;
>+		writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);
>+		spin_unlock_irqrestore(ap->lock, flags);
>+	}
>+	return count;
>+}
>+
> static ssize_t ahci_show_host_caps(struct device *dev,
> 				   struct device_attribute *attr, char *buf)
> {
>@@ -692,9 +893,14 @@ static int ahci_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
> 		 * Disable interrupts on Phy Ready. This keeps us from
> 		 * getting woken up due to spurious phy ready
> 		 * interrupts.
>+		 *
>+		 * However, when accounting_active is set, we do want
>+		 * the interrupts for accounting purposes.
> 		 */
>-		pp->intr_mask &= ~PORT_IRQ_PHYRDY;
>-		writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);
>+		if (!pp->accounting_active) {
>+			pp->intr_mask &= ~PORT_IRQ_PHYRDY;
>+			writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);
>+		}
> 
> 		sata_link_scr_lpm(link, policy, false);
> 	}
>@@ -1716,6 +1922,7 @@ static void ahci_handle_port_interrupt(struct ata_port *ap,
> 
> 	if (sata_lpm_ignore_phy_events(&ap->link)) {
> 		status &= ~PORT_IRQ_PHYRDY;
>+		account_alpm_stats(ap);
> 		ahci_scr_write(&ap->link, SCR_ERROR, SERR_PHYRDY_CHG);
> 	}
> 
>-- 
>2.5.0
>

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Attachments on bug 93035: 119971 | 119972 | 119974 | 119975 | 119976 | 119977 | 119978 | 119984 | 119990 | 119991 | 119992 | 119993 | 119994 | 119995 | 120057 | 120058 | 120059 | 120060 | 120061 | 120062 | 120063 | 120064 | 120068

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