Re: [dpdk-dev] [EXT] Re: [PATCH v4 1/1] bus/pci: optimise scanning with whitelist/blacklist

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

>-----Original Message-----
>From: Gaëtan Rivet <grive@u256.net>
>Sent: Saturday, May 2, 2020 2:30 AM
>To: Sunil Kumar Kori <skori@marvell.com>
>Cc: stephen@networkplumber.org; david.marchand@redhat.com; Jerin Jacob
>Kollanukkaran <jerinj@marvell.com>; dev@dpdk.org
>Subject: [EXT] Re: [PATCH v4 1/1] bus/pci: optimise scanning with
>whitelist/blacklist
>
>External Email
>
>----------------------------------------------------------------------
>Hello Sunil,
>
>It's pretty close, thanks. Unfortunately, I just have a few nits remaining.
>
>On 01/05/20 17:09 +0530, Sunil Kumar Kori wrote:
>> 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>
>> ---
>> v4:
>>  - Review comments incorporated (Gaeten and David).
>>  - Rebased on top of tree.
>> v3:
>>  - Remove __rte_experimental from private function.
>>  - Remove entry from map file too.
>> v2:
>>  - Added function to validate ignorance of device based on PCI address.
>>  - Marked device validation function as experimental.
>>
>>  drivers/bus/pci/bsd/pci.c    | 12 +++++++++++-
>>  drivers/bus/pci/linux/pci.c  |  3 +++  drivers/bus/pci/pci_common.c |
>> 33 ++++++++++++---------------------
>>  drivers/bus/pci/private.h    | 11 +++++++++++
>>  4 files changed, 37 insertions(+), 22 deletions(-)
>>
>> diff --git a/drivers/bus/pci/bsd/pci.c b/drivers/bus/pci/bsd/pci.c
>> index ebbfeb13a..709a1e7e5 100644
>> --- a/drivers/bus/pci/bsd/pci.c
>> +++ b/drivers/bus/pci/bsd/pci.c
>> @@ -338,6 +338,7 @@ rte_pci_scan(void)
>>  			.match_buf_len = sizeof(matches),
>>  			.matches = &matches[0],
>>  	};
>> +	struct rte_pci_addr pci_addr;
>>
>>  	/* for debug purposes, PCI can be disabled */
>>  	if (!rte_eal_has_pci())
>> @@ -357,9 +358,18 @@ 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;
>> +
>> +			if (rte_pci_ignore_device_addr(&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
>> ca783b157..ec347eff3 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 (rte_pci_ignore_device_addr(&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..d34e59536 100644
>> --- a/drivers/bus/pci/pci_common.c
>> +++ b/drivers/bus/pci/pci_common.c
>> @@ -42,14 +42,17 @@ const char *rte_pci_get_sysfs_path(void)
>>  	return path;
>>  }
>>
>> -static struct rte_devargs *pci_devargs_lookup(struct rte_pci_device
>> *dev)
>> +static struct rte_devargs *
>> +pci_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(&dev->addr, &addr))
>> +		if (rte_pci_addr_parse(devargs->name, &addr) < 0)
>> +			continue;
>> +
>> +		if (!rte_pci_addr_cmp(pci_addr, &addr))
>
>I'm really sorry, I was overzealous on your v4. I thought using
>devargs->bus->parse() was from your patch, but it was already there.
>
>It's even more shameful as it was me who wrote this.
>
>Anyway, it's much better looking this way, but it should be a separate patch.
>
No problem. I will revert this change to its original state and later will share separate
Patch to replace devargs->bus->parse.

>>  			return devargs;
>>  	}
>>  	return NULL;
>> @@ -63,7 +66,7 @@ pci_name_set(struct rte_pci_device *dev)
>>  	/* Each device has its internal, canonical name set. */
>>  	rte_pci_device_name(&dev->addr,
>>  			dev->name, sizeof(dev->name));
>> -	devargs = pci_devargs_lookup(dev);
>> +	devargs = pci_devargs_lookup(&dev->addr);
>>  	dev->device.devargs = devargs;
>>  	/* In blacklist mode, if the device is not blacklisted, no
>>  	 * rte_devargs exists for it.
>> @@ -293,23 +296,12 @@ rte_pci_probe(void)  {
>>  	struct rte_pci_device *dev = NULL;
>>  	size_t probed = 0, failed = 0;
>> -	struct rte_devargs *devargs;
>> -	int probe_all = 0;
>>  	int ret = 0;
>>
>> -	if (rte_pci_bus.bus.conf.scan_mode != RTE_BUS_SCAN_WHITELIST)
>> -		probe_all = 1;
>> -
>>  	FOREACH_DEVICE_ON_PCIBUS(dev) {
>>  		probed++;
>>
>> -		devargs = dev->device.devargs;
>> -		/* probe all or only whitelisted devices */
>> -		if (probe_all)
>> -			ret = pci_probe_all_drivers(dev);
>> -		else if (devargs != NULL &&
>> -			devargs->policy == RTE_DEV_WHITELISTED)
>> -			ret = pci_probe_all_drivers(dev);
>> +		ret = pci_probe_all_drivers(dev);
>>  		if (ret < 0) {
>>  			if (ret != -EEXIST) {
>>  				RTE_LOG(ERR, EAL, "Requested device "
>> @@ -589,10 +581,10 @@ pci_dma_unmap(struct rte_device *dev, void
>*addr, uint64_t iova, size_t len)
>>  	return -1;
>>  }
>>
>> -static bool
>> -pci_ignore_device(const struct rte_pci_device *dev)
>> +bool
>> +rte_pci_ignore_device_addr(const struct rte_pci_addr *pci_addr)
>
>I'd prefer naming this function rte_pci_ignore_device(), given that
>pci_ignore_device() disappears.
>
Ack.

>>  {
>> -	struct rte_devargs *devargs = dev->device.devargs;
>> +	struct rte_devargs *devargs = pci_devargs_lookup(pci_addr);
>>
>>  	switch (rte_pci_bus.bus.conf.scan_mode) {
>>  	case RTE_BUS_SCAN_WHITELIST:
>> @@ -627,8 +619,7 @@ rte_pci_get_iommu_class(void)
>>  		if (iommu_no_va == -1)
>>  			iommu_no_va = pci_device_iommu_support_va(dev)
>>  					? 0 : 1;
>> -		if (pci_ignore_device(dev))
>> -			continue;
>> +
>>  		if (dev->kdrv == RTE_KDRV_UNKNOWN ||
>>  		    dev->kdrv == RTE_KDRV_NONE)
>>  			continue;
>> diff --git a/drivers/bus/pci/private.h b/drivers/bus/pci/private.h
>> index a205d4d9f..3874219ba 100644
>> --- a/drivers/bus/pci/private.h
>> +++ b/drivers/bus/pci/private.h
>> @@ -42,6 +42,17 @@ 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,
>> + */
>> +bool rte_pci_ignore_device_addr(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
>> --
>> 2.17.1
>>
>
>Otherwise it looks good to me, almost finished!
>
>--
>Gaëtan