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authorRafal Kozik <rk@semihalf.com>2018-06-29 15:54:07 +0200
committerThomas Monjalon <thomas@monjalon.net>2018-06-30 00:12:58 +0200
commit4a928ef9f6114d119899b95ba47acc0e9562f7a5 (patch)
treeacde1f63dcda5a260665d94f13012c9e79aedb10
parent1d20a073fa5eb04b9ab4a06ea71b770c17bc35c6 (diff)
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bus/pci: enable write combining during mapping
Write combining (WC) increases NIC performance by making better utilization of PCI bus, but cannot be used by all PMDs. It will be enabled only if RTE_PCI_DRV_WC_ACTIVATE will be set in drivers flags. For proper work also igb_uio driver must be loaded with wc_activate set to 1. When mapping PCI resources, firstly check if it support WC and then try to use it. In case of failure, it will fallback to normal mode. Signed-off-by: Rafal Kozik <rk@semihalf.com> Acked-by: Bruce Richardson <bruce.richardson@intel.com>
-rw-r--r--drivers/bus/pci/linux/pci_uio.c47
-rw-r--r--drivers/bus/pci/rte_bus_pci.h2
2 files changed, 37 insertions, 12 deletions
diff --git a/drivers/bus/pci/linux/pci_uio.c b/drivers/bus/pci/linux/pci_uio.c
index d423e4b..a7c1442 100644
--- a/drivers/bus/pci/linux/pci_uio.c
+++ b/drivers/bus/pci/linux/pci_uio.c
@@ -282,22 +282,19 @@ int
pci_uio_map_resource_by_index(struct rte_pci_device *dev, int res_idx,
struct mapped_pci_resource *uio_res, int map_idx)
{
- int fd;
+ int fd = -1;
char devname[PATH_MAX];
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 +306,37 @@ 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);
+
+ if (access(devname, R_OK|W_OK) != -1) {
+ fd = open(devname, O_RDWR);
+ if (fd < 0)
+ RTE_LOG(INFO, EAL, "%s cannot be mapped. "
+ "Fall-back to non prefetchable mode.\n",
+ devname);
+ }
+ }
+
+ 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 458e6d0..828acc5 100644
--- a/drivers/bus/pci/rte_bus_pci.h
+++ b/drivers/bus/pci/rte_bus_pci.h
@@ -135,6 +135,8 @@ 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 */