[dpdk-dev,3/4] eal: enable WC during resources mapping
diff mbox

Message ID 1523455637-31719-4-git-send-email-rk@semihalf.com
State Superseded, archived
Delegated to: Thomas Monjalon
Headers show

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Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation success Compilation OK

Commit Message

Rafal Kozik April 11, 2018, 2:07 p.m. UTC
Write combining (wc) increase NIC performenca by making better
utilization of PCI bus, but cannot be used by all PMD.

It will be enable only if RTE_PCI_DRV_WC_ACTIVATE will be set in
drivers flags. For proper work also igb driver must be loaded with
wc_activate set to 1.

When mapping PCI resources firstly try to us wc.
If it is not supported it will fallback to normal mode.

Signed-off-by: Rafal Kozik <rk@semihalf.com>
---
 drivers/bus/pci/linux/pci_uio.c | 39 ++++++++++++++++++++++++++++-----------
 drivers/bus/pci/rte_bus_pci.h   |  2 ++
 2 files changed, 30 insertions(+), 11 deletions(-)

Comments

Ferruh Yigit June 27, 2018, 4:41 p.m. UTC | #1
On 4/11/2018 3:07 PM, Rafal Kozik wrote:
> Write combining (wc) increase NIC performenca by making better
> utilization of PCI bus, but cannot be used by all PMD.
> 
> It will be enable only if RTE_PCI_DRV_WC_ACTIVATE will be set in
> drivers flags. For proper work also igb driver must be loaded with
> wc_activate set to 1.
> 
> When mapping PCI resources firstly try to us wc.
> If it is not supported it will fallback to normal mode.
> 
> Signed-off-by: Rafal Kozik <rk@semihalf.com>
> ---
>  drivers/bus/pci/linux/pci_uio.c | 39 ++++++++++++++++++++++++++++-----------
>  drivers/bus/pci/rte_bus_pci.h   |  2 ++
>  2 files changed, 30 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/bus/pci/linux/pci_uio.c b/drivers/bus/pci/linux/pci_uio.c
> index d423e4b..a1570c9 100644
> --- a/drivers/bus/pci/linux/pci_uio.c
> +++ b/drivers/bus/pci/linux/pci_uio.c
> @@ -287,17 +287,14 @@ pci_uio_map_resource_by_index(struct rte_pci_device *dev, int res_idx,
>  	void *mapaddr;
>  	struct rte_pci_addr *loc;
>  	struct pci_map *maps;
> +	int wc_activate = 0;
> +
> +	if (dev->driver != NULL)
> +		wc_activate = dev->driver->drv_flags & RTE_PCI_DRV_WC_ACTIVATE;
>  
>  	loc = &dev->addr;
>  	maps = uio_res->maps;
>  
> -	/* update devname for mmap  */
> -	snprintf(devname, sizeof(devname),
> -			"%s/" PCI_PRI_FMT "/resource%d",
> -			rte_pci_get_sysfs_path(),
> -			loc->domain, loc->bus, loc->devid,
> -			loc->function, res_idx);
> -
>  	/* allocate memory to keep path */
>  	maps[map_idx].path = rte_malloc(NULL, strlen(devname) + 1, 0);
>  	if (maps[map_idx].path == NULL) {
> @@ -309,11 +306,31 @@ pci_uio_map_resource_by_index(struct rte_pci_device *dev, int res_idx,
>  	/*
>  	 * open resource file, to mmap it
>  	 */
> -	fd = open(devname, O_RDWR);
> -	if (fd < 0) {
> -		RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
> +	if (wc_activate) {
> +		/* update devname for mmap  */
> +		snprintf(devname, sizeof(devname),
> +			"%s/" PCI_PRI_FMT "/resource%d_wc",
> +			rte_pci_get_sysfs_path(),
> +			loc->domain, loc->bus, loc->devid,
> +			loc->function, res_idx);
> +
> +		fd = open(devname, O_RDWR);
> +	}
> +
> +	if (!wc_activate || fd < 0) {

"fd" may be used uninitialized here, although its value doesn't affect the
branch taken it can be good to initialize it for any possible static analyzer
warning.

> +		snprintf(devname, sizeof(devname),
> +			"%s/" PCI_PRI_FMT "/resource%d",
> +			rte_pci_get_sysfs_path(),
> +			loc->domain, loc->bus, loc->devid,
> +			loc->function, res_idx);
> +
> +		/* then try to map resource file */
> +		fd = open(devname, O_RDWR);
> +		if (fd < 0) {
> +			RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
>  				devname, strerror(errno));
> -		goto error;
> +			goto error;
> +		}
>  	}
>  
>  	/* try mapping somewhere close to the end of hugepages */
> diff --git a/drivers/bus/pci/rte_bus_pci.h b/drivers/bus/pci/rte_bus_pci.h
> index 357afb9..b7bcce3 100644
> --- a/drivers/bus/pci/rte_bus_pci.h
> +++ b/drivers/bus/pci/rte_bus_pci.h
> @@ -132,6 +132,8 @@ struct rte_pci_bus {
>  
>  /** Device needs PCI BAR mapping (done with either IGB_UIO or VFIO) */
>  #define RTE_PCI_DRV_NEED_MAPPING 0x0001
> +/** Device needs PCI BAR mapping with enabled write combining (wc) */
> +#define RTE_PCI_DRV_WC_ACTIVATE 0x0002
>  /** Device driver supports link state interrupt */
>  #define RTE_PCI_DRV_INTR_LSC	0x0008
>  /** Device driver supports device removal interrupt */
>
Rafal Kozik June 28, 2018, 1:06 p.m. UTC | #2
2018-06-27 18:41 GMT+02:00 Ferruh Yigit <ferruh.yigit@intel.com>:
> On 4/11/2018 3:07 PM, Rafal Kozik wrote:
>> Write combining (wc) increase NIC performenca by making better
>> utilization of PCI bus, but cannot be used by all PMD.
>>
>> It will be enable only if RTE_PCI_DRV_WC_ACTIVATE will be set in
>> drivers flags. For proper work also igb driver must be loaded with
>> wc_activate set to 1.
>>
>> When mapping PCI resources firstly try to us wc.
>> If it is not supported it will fallback to normal mode.
>>
>> Signed-off-by: Rafal Kozik <rk@semihalf.com>
>> ---
>>  drivers/bus/pci/linux/pci_uio.c | 39 ++++++++++++++++++++++++++++-----------
>>  drivers/bus/pci/rte_bus_pci.h   |  2 ++
>>  2 files changed, 30 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/bus/pci/linux/pci_uio.c b/drivers/bus/pci/linux/pci_uio.c
>> index d423e4b..a1570c9 100644
>> --- a/drivers/bus/pci/linux/pci_uio.c
>> +++ b/drivers/bus/pci/linux/pci_uio.c
>> @@ -287,17 +287,14 @@ pci_uio_map_resource_by_index(struct rte_pci_device *dev, int res_idx,
>>       void *mapaddr;
>>       struct rte_pci_addr *loc;
>>       struct pci_map *maps;
>> +     int wc_activate = 0;
>> +
>> +     if (dev->driver != NULL)
>> +             wc_activate = dev->driver->drv_flags & RTE_PCI_DRV_WC_ACTIVATE;
>>
>>       loc = &dev->addr;
>>       maps = uio_res->maps;
>>
>> -     /* update devname for mmap  */
>> -     snprintf(devname, sizeof(devname),
>> -                     "%s/" PCI_PRI_FMT "/resource%d",
>> -                     rte_pci_get_sysfs_path(),
>> -                     loc->domain, loc->bus, loc->devid,
>> -                     loc->function, res_idx);
>> -
>>       /* allocate memory to keep path */
>>       maps[map_idx].path = rte_malloc(NULL, strlen(devname) + 1, 0);
>>       if (maps[map_idx].path == NULL) {
>> @@ -309,11 +306,31 @@ pci_uio_map_resource_by_index(struct rte_pci_device *dev, int res_idx,
>>       /*
>>        * open resource file, to mmap it
>>        */
>> -     fd = open(devname, O_RDWR);
>> -     if (fd < 0) {
>> -             RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
>> +     if (wc_activate) {
>> +             /* update devname for mmap  */
>> +             snprintf(devname, sizeof(devname),
>> +                     "%s/" PCI_PRI_FMT "/resource%d_wc",
>> +                     rte_pci_get_sysfs_path(),
>> +                     loc->domain, loc->bus, loc->devid,
>> +                     loc->function, res_idx);
>> +
>> +             fd = open(devname, O_RDWR);
>> +     }
>> +
>> +     if (!wc_activate || fd < 0) {
>
> "fd" may be used uninitialized here, although its value doesn't affect the
> branch taken it can be good to initialize it for any possible static analyzer
> warning.
>

I will fix it in new, rebased patch set.

>> +             snprintf(devname, sizeof(devname),
>> +                     "%s/" PCI_PRI_FMT "/resource%d",
>> +                     rte_pci_get_sysfs_path(),
>> +                     loc->domain, loc->bus, loc->devid,
>> +                     loc->function, res_idx);
>> +
>> +             /* then try to map resource file */
>> +             fd = open(devname, O_RDWR);
>> +             if (fd < 0) {
>> +                     RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
>>                               devname, strerror(errno));
>> -             goto error;
>> +                     goto error;
>> +             }
>>       }
>>
>>       /* try mapping somewhere close to the end of hugepages */
>> diff --git a/drivers/bus/pci/rte_bus_pci.h b/drivers/bus/pci/rte_bus_pci.h
>> index 357afb9..b7bcce3 100644
>> --- a/drivers/bus/pci/rte_bus_pci.h
>> +++ b/drivers/bus/pci/rte_bus_pci.h
>> @@ -132,6 +132,8 @@ struct rte_pci_bus {
>>
>>  /** Device needs PCI BAR mapping (done with either IGB_UIO or VFIO) */
>>  #define RTE_PCI_DRV_NEED_MAPPING 0x0001
>> +/** Device needs PCI BAR mapping with enabled write combining (wc) */
>> +#define RTE_PCI_DRV_WC_ACTIVATE 0x0002
>>  /** Device driver supports link state interrupt */
>>  #define RTE_PCI_DRV_INTR_LSC 0x0008
>>  /** Device driver supports device removal interrupt */
>>
>

Patch
diff mbox

diff --git a/drivers/bus/pci/linux/pci_uio.c b/drivers/bus/pci/linux/pci_uio.c
index d423e4b..a1570c9 100644
--- a/drivers/bus/pci/linux/pci_uio.c
+++ b/drivers/bus/pci/linux/pci_uio.c
@@ -287,17 +287,14 @@  pci_uio_map_resource_by_index(struct rte_pci_device *dev, int res_idx,
 	void *mapaddr;
 	struct rte_pci_addr *loc;
 	struct pci_map *maps;
+	int wc_activate = 0;
+
+	if (dev->driver != NULL)
+		wc_activate = dev->driver->drv_flags & RTE_PCI_DRV_WC_ACTIVATE;
 
 	loc = &dev->addr;
 	maps = uio_res->maps;
 
-	/* update devname for mmap  */
-	snprintf(devname, sizeof(devname),
-			"%s/" PCI_PRI_FMT "/resource%d",
-			rte_pci_get_sysfs_path(),
-			loc->domain, loc->bus, loc->devid,
-			loc->function, res_idx);
-
 	/* allocate memory to keep path */
 	maps[map_idx].path = rte_malloc(NULL, strlen(devname) + 1, 0);
 	if (maps[map_idx].path == NULL) {
@@ -309,11 +306,31 @@  pci_uio_map_resource_by_index(struct rte_pci_device *dev, int res_idx,
 	/*
 	 * open resource file, to mmap it
 	 */
-	fd = open(devname, O_RDWR);
-	if (fd < 0) {
-		RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
+	if (wc_activate) {
+		/* update devname for mmap  */
+		snprintf(devname, sizeof(devname),
+			"%s/" PCI_PRI_FMT "/resource%d_wc",
+			rte_pci_get_sysfs_path(),
+			loc->domain, loc->bus, loc->devid,
+			loc->function, res_idx);
+
+		fd = open(devname, O_RDWR);
+	}
+
+	if (!wc_activate || fd < 0) {
+		snprintf(devname, sizeof(devname),
+			"%s/" PCI_PRI_FMT "/resource%d",
+			rte_pci_get_sysfs_path(),
+			loc->domain, loc->bus, loc->devid,
+			loc->function, res_idx);
+
+		/* then try to map resource file */
+		fd = open(devname, O_RDWR);
+		if (fd < 0) {
+			RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
 				devname, strerror(errno));
-		goto error;
+			goto error;
+		}
 	}
 
 	/* try mapping somewhere close to the end of hugepages */
diff --git a/drivers/bus/pci/rte_bus_pci.h b/drivers/bus/pci/rte_bus_pci.h
index 357afb9..b7bcce3 100644
--- a/drivers/bus/pci/rte_bus_pci.h
+++ b/drivers/bus/pci/rte_bus_pci.h
@@ -132,6 +132,8 @@  struct rte_pci_bus {
 
 /** Device needs PCI BAR mapping (done with either IGB_UIO or VFIO) */
 #define RTE_PCI_DRV_NEED_MAPPING 0x0001
+/** Device needs PCI BAR mapping with enabled write combining (wc) */
+#define RTE_PCI_DRV_WC_ACTIVATE 0x0002
 /** Device driver supports link state interrupt */
 #define RTE_PCI_DRV_INTR_LSC	0x0008
 /** Device driver supports device removal interrupt */