Re: [dpdk-dev] [PATCH v2 1/1] bus/pci: optimise scanning with whitelist/blacklist

[Sunil Kumar Kori <skori@marvell.com>]

Hello David and Stephen,

I have uploaded second version of patch as per your suggestion. 
Please have a look and ack if it looks okay.

Regards
Sunil Kumar Kori

>-----Original Message-----
>From: Sunil Kumar Kori <skori@marvell.com>
>Sent: Tuesday, April 7, 2020 2:59 PM
>To: stephen@networkplumber.org; david.marchand@redhat.com; Jerin Jacob
>Kollanukkaran <jerinj@marvell.com>
>Cc: dev@dpdk.org; Sunil Kumar Kori <skori@marvell.com>
>Subject: [PATCH v2 1/1] bus/pci: optimise scanning with whitelist/blacklist
>
>rte_bus_scan API scans all the available PCI devices irrespective of white or
>black listing parameters then further devices are probed based on white or
>black listing parameters. So unnecessary CPU cycles are wasted during
>rte_pci_scan.
>
>For Octeontx2 platform with core frequency 2.4 Ghz, rte_bus_scan consumes
>around 26ms to scan around 90 PCI devices but all may not be used by the
>application. So for the application which uses 2 NICs, rte_bus_scan consumes
>few microseconds and rest time is saved with this patch.
>
>Patch restricts devices to be scanned as per below mentioned conditions:
> - All devices will be scanned if no parameters are passed.
> - Only white listed devices will be scanned if white list is available.
> - All devices, except black listed, will be scanned if black list is
>   available.
>
>Signed-off-by: Sunil Kumar Kori <skori@marvell.com>
>---
>v2:
> - Added function to validate ignorance of device based on PCI address.
> - Marked device validation function as experimental.
>
> drivers/bus/pci/bsd/pci.c               | 15 ++++++++++-
> drivers/bus/pci/linux/pci.c             |  3 +++
> drivers/bus/pci/pci_common.c            | 34 +++++++++++++++++++++++++
> drivers/bus/pci/private.h               | 12 +++++++++
> drivers/bus/pci/rte_bus_pci_version.map |  5 ++++
> 5 files changed, 68 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/bus/pci/bsd/pci.c b/drivers/bus/pci/bsd/pci.c index
>ebbfeb13a..074f4556e 100644
>--- a/drivers/bus/pci/bsd/pci.c
>+++ b/drivers/bus/pci/bsd/pci.c
>@@ -338,6 +338,9 @@ rte_pci_scan(void)
> 			.match_buf_len = sizeof(matches),
> 			.matches = &matches[0],
> 	};
>+	struct rte_pci_addr pci_addr;
>+
>+	memset(&pci_addr, 0, sizeof(struct rte_pci_addr));
>
> 	/* for debug purposes, PCI can be disabled */
> 	if (!rte_eal_has_pci())
>@@ -357,9 +360,19 @@ rte_pci_scan(void)
> 			goto error;
> 		}
>
>-		for (i = 0; i < conf_io.num_matches; i++)
>+		for (i = 0; i < conf_io.num_matches; i++) {
>+			pci_addr.domain = matches[i].pc_sel.pc_domain;
>+			pci_addr.bus = matches[i].pc_sel.pc_bus;
>+			pci_addr.devid = matches[i].pc_sel.pc_dev;
>+			pci_addr.function = matches[i].pc_sel.pc_func;
>+
>+			/* Check that device should be ignored or not  */
>+			if (pci_addr_ignore_device(&pci_addr))
>+				continue;
>+
> 			if (pci_scan_one(fd, &matches[i]) < 0)
> 				goto error;
>+		}
>
> 		dev_count += conf_io.num_matches;
> 	} while(conf_io.status == PCI_GETCONF_MORE_DEVS); diff --git
>a/drivers/bus/pci/linux/pci.c b/drivers/bus/pci/linux/pci.c index
>71b0a3053..92bdad826 100644
>--- a/drivers/bus/pci/linux/pci.c
>+++ b/drivers/bus/pci/linux/pci.c
>@@ -487,6 +487,9 @@ rte_pci_scan(void)
> 		if (parse_pci_addr_format(e->d_name, sizeof(e->d_name),
>&addr) != 0)
> 			continue;
>
>+		if (pci_addr_ignore_device(&addr))
>+			continue;
>+
> 		snprintf(dirname, sizeof(dirname), "%s/%s",
> 				rte_pci_get_sysfs_path(), e->d_name);
>
>diff --git a/drivers/bus/pci/pci_common.c b/drivers/bus/pci/pci_common.c
>index 3f5542076..a350a1993 100644
>--- a/drivers/bus/pci/pci_common.c
>+++ b/drivers/bus/pci/pci_common.c
>@@ -589,6 +589,40 @@ pci_dma_unmap(struct rte_device *dev, void *addr,
>uint64_t iova, size_t len)
> 	return -1;
> }
>
>+static struct rte_devargs *
>+pci_addr_devargs_lookup(const struct rte_pci_addr *pci_addr) {
>+	struct rte_devargs *devargs;
>+	struct rte_pci_addr addr;
>+
>+	RTE_EAL_DEVARGS_FOREACH("pci", devargs) {
>+		devargs->bus->parse(devargs->name, &addr);
>+		if (!rte_pci_addr_cmp(pci_addr, &addr))
>+			return devargs;
>+	}
>+	return NULL;
>+}
>+
>+bool
>+pci_addr_ignore_device(const struct rte_pci_addr *pci_addr) {
>+	struct rte_devargs *devargs = pci_addr_devargs_lookup(pci_addr);
>+
>+	switch (rte_pci_bus.bus.conf.scan_mode) {
>+	case RTE_BUS_SCAN_WHITELIST:
>+		if (devargs && devargs->policy == RTE_DEV_WHITELISTED)
>+			return false;
>+		break;
>+	case RTE_BUS_SCAN_UNDEFINED:
>+	case RTE_BUS_SCAN_BLACKLIST:
>+		if (devargs == NULL ||
>+		    devargs->policy != RTE_DEV_BLACKLISTED)
>+			return false;
>+		break;
>+	}
>+	return true;
>+}
>+
> static bool
> pci_ignore_device(const struct rte_pci_device *dev)  { diff --git
>a/drivers/bus/pci/private.h b/drivers/bus/pci/private.h index
>a205d4d9f..25075b806 100644
>--- a/drivers/bus/pci/private.h
>+++ b/drivers/bus/pci/private.h
>@@ -42,6 +42,18 @@ int rte_pci_scan(void);  void  pci_name_set(struct
>rte_pci_device *dev);
>
>+/**
>+ * Validate whether a device with given pci address should be ignored or not.
>+ *
>+ * @param pci_addr
>+ *	PCI address of device to be validated
>+ * @return
>+ *	1: if device is to be ignored,
>+ *	0: if device is to be scanned,
>+ */
>+__rte_experimental
>+bool pci_addr_ignore_device(const struct rte_pci_addr *pci_addr);
>+
> /**
>  * Add a PCI device to the PCI Bus (append to PCI Device list). This function
>  * also updates the bus references of the PCI Device (and the generic device
>diff --git a/drivers/bus/pci/rte_bus_pci_version.map
>b/drivers/bus/pci/rte_bus_pci_version.map
>index 012d817e1..da4ae2640 100644
>--- a/drivers/bus/pci/rte_bus_pci_version.map
>+++ b/drivers/bus/pci/rte_bus_pci_version.map
>@@ -16,3 +16,8 @@ DPDK_20.0 {
>
> 	local: *;
> };
>+
>+EXPERIMENTAL {
>+	# added in 20.05
>+	pci_addr_ignore_device;
>+};
>--
>2.17.1