[dpdk-dev] [PATCH v3 4/5] eal: add per rx queue interrupt handling based on VFIO

Neil Horman nhorman at tuxdriver.com
Thu Feb 19 14:04:07 CET 2015
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On Thu, Feb 19, 2015 at 08:10:47AM +0000, Zhou, Danny wrote:
> 
> 
> > -----Original Message-----
> > From: Neil Horman [mailto:nhorman at tuxdriver.com]
> > Sent: Tuesday, February 17, 2015 11:59 PM
> > To: Zhou, Danny
> > Cc: dev at dpdk.org
> > Subject: Re: [dpdk-dev] [PATCH v3 4/5] eal: add per rx queue interrupt handling based on VFIO
> > 
> > On Tue, Feb 17, 2015 at 09:47:18PM +0800, Zhou Danny wrote:
> > > v3 changes:
> > > - Fix review comments
> > >
> > > v2 changes:
> > > - Fix compilation issue for a missed header file
> > > - Bug fix: free unreleased resources on the exception path before return
> > > - Consolidate coding style related review comments
> > >
> > > This patch does below:
> > > - Create multiple VFIO eventfd for rx queues.
> > > - Handle per rx queue interrupt.
> > > - Eliminate unnecessary suspended DPDK polling thread wakeup mechanism
> > > for rx interrupt by allowing polling thread epoll_wait rx queue
> > > interrupt notification.
> > >
> > > Signed-off-by: Danny Zhou <danny.zhou at intel.com>
> > > Tested-by: Yong Liu <yong.liu at intel.com>
> > > ---
> > >  lib/librte_eal/common/include/rte_eal.h            |  12 ++
> > >  lib/librte_eal/linuxapp/eal/Makefile               |   1 +
> > >  lib/librte_eal/linuxapp/eal/eal_interrupts.c       | 190 ++++++++++++++++-----
> > >  lib/librte_eal/linuxapp/eal/eal_pci_vfio.c         |  12 +-
> > >  .../linuxapp/eal/include/exec-env/rte_interrupts.h |   4 +
> > >  5 files changed, 175 insertions(+), 44 deletions(-)
> > >
> > > diff --git a/lib/librte_eal/common/include/rte_eal.h b/lib/librte_eal/common/include/rte_eal.h
> > > index f4ecd2e..d81331f 100644
> > > --- a/lib/librte_eal/common/include/rte_eal.h
> > > +++ b/lib/librte_eal/common/include/rte_eal.h
> > > @@ -150,6 +150,18 @@ int rte_eal_iopl_init(void);
> > >   *   - On failure, a negative error value.
> > >   */
> > >  int rte_eal_init(int argc, char **argv);
> > > +
> > > +/**
> > > + * @param port_id
> > > + *   the port id
> > > + * @param queue_id
> > > + *   the queue id
> > > + * @return
> > > + *   - On success, return 0
> > > + *   - On failure, returns -1.
> > > + */
> > > +int rte_eal_wait_rx_intr(uint8_t port_id, uint8_t queue_id);
> > > +
> > >  /**
> > >   * Usage function typedef used by the application usage function.
> > >   *
> > > diff --git a/lib/librte_eal/linuxapp/eal/Makefile b/lib/librte_eal/linuxapp/eal/Makefile
> > > index e117cec..c593dfa 100644
> > > --- a/lib/librte_eal/linuxapp/eal/Makefile
> > > +++ b/lib/librte_eal/linuxapp/eal/Makefile
> > > @@ -43,6 +43,7 @@ CFLAGS += -I$(SRCDIR)/include
> > >  CFLAGS += -I$(RTE_SDK)/lib/librte_eal/common
> > >  CFLAGS += -I$(RTE_SDK)/lib/librte_eal/common/include
> > >  CFLAGS += -I$(RTE_SDK)/lib/librte_ring
> > > +CFLAGS += -I$(RTE_SDK)/lib/librte_mbuf
> > >  CFLAGS += -I$(RTE_SDK)/lib/librte_mempool
> > >  CFLAGS += -I$(RTE_SDK)/lib/librte_malloc
> > >  CFLAGS += -I$(RTE_SDK)/lib/librte_ether
> > > diff --git a/lib/librte_eal/linuxapp/eal/eal_interrupts.c b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
> > > index dc2668a..97215ad 100644
> > > --- a/lib/librte_eal/linuxapp/eal/eal_interrupts.c
> > > +++ b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
> > > @@ -64,6 +64,7 @@
> > >  #include <rte_malloc.h>
> > >  #include <rte_errno.h>
> > >  #include <rte_spinlock.h>
> > > +#include <rte_ethdev.h>
> > >
> > >  #include "eal_private.h"
> > >  #include "eal_vfio.h"
> > > @@ -127,6 +128,9 @@ static pthread_t intr_thread;
> > >  #ifdef VFIO_PRESENT
> > >
> > >  #define IRQ_SET_BUF_LEN  (sizeof(struct vfio_irq_set) + sizeof(int))
> > > +/* irq set buffer length for queue interrupts and LSC interrupt */
> > > +#define MSIX_IRQ_SET_BUF_LEN (sizeof(struct vfio_irq_set) + \
> > > +				sizeof(int) * (VFIO_MAX_QUEUE_ID + 1))
> > >
> > >  /* enable legacy (INTx) interrupts */
> > >  static int
> > > @@ -218,10 +222,10 @@ vfio_disable_intx(struct rte_intr_handle *intr_handle) {
> > >  	return 0;
> > >  }
> > >
> > > -/* enable MSI-X interrupts */
> > > +/* enable MSI interrupts */
> > >  static int
> > >  vfio_enable_msi(struct rte_intr_handle *intr_handle) {
> > > -	int len, ret;
> > > +	int len, ret, max_intr;
> > >  	char irq_set_buf[IRQ_SET_BUF_LEN];
> > >  	struct vfio_irq_set *irq_set;
> > >  	int *fd_ptr;
> > > @@ -230,12 +234,19 @@ vfio_enable_msi(struct rte_intr_handle *intr_handle) {
> > >
> > >  	irq_set = (struct vfio_irq_set *) irq_set_buf;
> > >  	irq_set->argsz = len;
> > > -	irq_set->count = 1;
> > > +	if ((!intr_handle->max_intr) ||
> > > +		(intr_handle->max_intr > VFIO_MAX_QUEUE_ID))
> > > +		max_intr = VFIO_MAX_QUEUE_ID + 1;
> > > +	else
> > > +		max_intr = intr_handle->max_intr;
> > > +
> > > +	irq_set->count = max_intr;
> > >  	irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER;
> > >  	irq_set->index = VFIO_PCI_MSI_IRQ_INDEX;
> > >  	irq_set->start = 0;
> > >  	fd_ptr = (int *) &irq_set->data;
> > > -	*fd_ptr = intr_handle->fd;
> > > +	memcpy(fd_ptr, intr_handle->queue_fd, sizeof(intr_handle->queue_fd));
> > > +	fd_ptr[max_intr - 1] = intr_handle->fd;
> > >
> > >  	ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
> > >
> > > @@ -244,27 +255,10 @@ vfio_enable_msi(struct rte_intr_handle *intr_handle) {
> > >  						intr_handle->fd);
> > >  		return -1;
> > >  	}
> > > -
> > > -	/* manually trigger interrupt to enable it */
> > > -	memset(irq_set, 0, len);
> > > -	len = sizeof(struct vfio_irq_set);
> > > -	irq_set->argsz = len;
> > > -	irq_set->count = 1;
> > > -	irq_set->flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_TRIGGER;
> > > -	irq_set->index = VFIO_PCI_MSI_IRQ_INDEX;
> > > -	irq_set->start = 0;
> > > -
> > > -	ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
> > > -
> > > -	if (ret) {
> > > -		RTE_LOG(ERR, EAL, "Error triggering MSI interrupts for fd %d\n",
> > > -						intr_handle->fd);
> > > -		return -1;
> > > -	}
> > >  	return 0;
> > >  }
> > >
> > > -/* disable MSI-X interrupts */
> > > +/* disable MSI interrupts */
> > >  static int
> > >  vfio_disable_msi(struct rte_intr_handle *intr_handle) {
> > >  	struct vfio_irq_set *irq_set;
> > > @@ -292,8 +286,8 @@ vfio_disable_msi(struct rte_intr_handle *intr_handle) {
> > >  /* enable MSI-X interrupts */
> > >  static int
> > >  vfio_enable_msix(struct rte_intr_handle *intr_handle) {
> > > -	int len, ret;
> > > -	char irq_set_buf[IRQ_SET_BUF_LEN];
> > > +	int len, ret, max_intr;
> > > +	char irq_set_buf[MSIX_IRQ_SET_BUF_LEN];
> > >  	struct vfio_irq_set *irq_set;
> > >  	int *fd_ptr;
> > >
> > > @@ -301,12 +295,19 @@ vfio_enable_msix(struct rte_intr_handle *intr_handle) {
> > >
> > >  	irq_set = (struct vfio_irq_set *) irq_set_buf;
> > >  	irq_set->argsz = len;
> > > -	irq_set->count = 1;
> > > +	if ((!intr_handle->max_intr) ||
> > > +		(intr_handle->max_intr > VFIO_MAX_QUEUE_ID))
> > > +		max_intr = VFIO_MAX_QUEUE_ID + 1;
> > > +	else
> > > +		max_intr = intr_handle->max_intr;
> > > +
> > > +	irq_set->count = max_intr;
> > >  	irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER;
> > >  	irq_set->index = VFIO_PCI_MSIX_IRQ_INDEX;
> > >  	irq_set->start = 0;
> > >  	fd_ptr = (int *) &irq_set->data;
> > > -	*fd_ptr = intr_handle->fd;
> > > +	memcpy(fd_ptr, intr_handle->queue_fd, sizeof(intr_handle->queue_fd));
> > > +	fd_ptr[max_intr - 1] = intr_handle->fd;
> > >
> > >  	ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
> > >
> > > @@ -316,22 +317,6 @@ vfio_enable_msix(struct rte_intr_handle *intr_handle) {
> > >  		return -1;
> > >  	}
> > >
> > > -	/* manually trigger interrupt to enable it */
> > > -	memset(irq_set, 0, len);
> > > -	len = sizeof(struct vfio_irq_set);
> > > -	irq_set->argsz = len;
> > > -	irq_set->count = 1;
> > > -	irq_set->flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_TRIGGER;
> > > -	irq_set->index = VFIO_PCI_MSIX_IRQ_INDEX;
> > > -	irq_set->start = 0;
> > > -
> > > -	ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
> > > -
> > > -	if (ret) {
> > > -		RTE_LOG(ERR, EAL, "Error triggering MSI-X interrupts for fd %d\n",
> > > -						intr_handle->fd);
> > > -		return -1;
> > > -	}
> > >  	return 0;
> > >  }
> > >
> > > @@ -339,7 +324,7 @@ vfio_enable_msix(struct rte_intr_handle *intr_handle) {
> > >  static int
> > >  vfio_disable_msix(struct rte_intr_handle *intr_handle) {
> > >  	struct vfio_irq_set *irq_set;
> > > -	char irq_set_buf[IRQ_SET_BUF_LEN];
> > > +	char irq_set_buf[MSIX_IRQ_SET_BUF_LEN];
> > >  	int len, ret;
> > >
> > >  	len = sizeof(struct vfio_irq_set);
> > > @@ -824,3 +809,122 @@ rte_eal_intr_init(void)
> > >  	return -ret;
> > >  }
> > >
> > > +static void
> > > +eal_intr_process_rx_interrupts(uint8_t port_id,
> > > +			struct epoll_event *events, int nfds)
> > > +{
> > > +	int n, bytes_read;
> > > +	union rte_intr_read_buffer buf;
> > > +	struct rte_intr_handle intr_handle =
> > > +				rte_eth_devices[port_id].pci_dev->intr_handle;
> > > +
> > > +	for (n = 0; n < nfds; n++) {
> > > +		/* set the length to be read for different handle type */
> > > +		switch (intr_handle.type) {
> > > +		case RTE_INTR_HANDLE_UIO:
> > > +			bytes_read = sizeof(buf.uio_intr_count);
> > > +			break;
> > > +		case RTE_INTR_HANDLE_ALARM:
> > > +			bytes_read = sizeof(buf.timerfd_num);
> > > +			break;
> > > +#ifdef VFIO_PRESENT
> > > +		case RTE_INTR_HANDLE_VFIO_MSIX:
> > > +		case RTE_INTR_HANDLE_VFIO_MSI:
> > > +		case RTE_INTR_HANDLE_VFIO_LEGACY:
> > > +			bytes_read = sizeof(buf.vfio_intr_count);
> > > +			break;
> > > +#endif
> > > +		default:
> > > +			bytes_read = 1;
> > > +			break;
> > > +		}
> > > +
> > > +		/**
> > > +		* read out to clear the ready-to-be-read flag
> > > +		* for epoll_wait.
> > > +		*/
> > > +		bytes_read = read(events[n].data.fd, &buf, bytes_read);
> > > +		if (bytes_read < 0)
> > > +			RTE_LOG(ERR, EAL, "Error reading from file "
> > > +				"descriptor %d: %s\n", events[n].data.fd,
> > > +							strerror(errno));
> > > +		else if (bytes_read == 0)
> > > +			RTE_LOG(ERR, EAL, "Read nothing from file "
> > > +				"descriptor %d\n", events[n].data.fd);
> > > +	}
> > > +}
> > > +
> > > +static void
> > > +eal_intr_handle_rx_interrupts(uint8_t port_id, int pfd, unsigned totalfds)
> > > +{
> > > +	struct epoll_event events[totalfds];
> > > +	int nfds = 0;
> > > +
> > > +	do {
> > > +		nfds = epoll_wait(pfd, events, totalfds,
> > > +				EAL_INTR_EPOLL_WAIT_FOREVER);
> > > +		/* epoll_wait fail */
> > > +		if (nfds < 0) {
> > > +			RTE_LOG(ERR, EAL,
> > > +				"epoll_wait returns with fail\n");
> > > +			return;
> > > +		}
> > > +	} while (nfds == 0);
> > > +
> > > +	/* epoll_wait has at least one fd ready to read */
> > > +	eal_intr_process_rx_interrupts(port_id, events, nfds);
> > > +}
> > > +
> > > +int
> > > +rte_eal_wait_rx_intr(uint8_t port_id, uint8_t queue_id)
> > > +{
> > > +	struct rte_intr_handle intr_handle =
> > > +				rte_eth_devices[port_id].pci_dev->intr_handle;
> > > +	struct epoll_event ev;
> > > +	unsigned numfds = 0;
> > > +
> > > +	/* create epoll fd */
> > > +	int pfd = epoll_create(1);
> > > +	if (pfd < 0) {
> > > +		RTE_LOG(ERR, EAL, "Cannot create epoll instance\n");
> > > +		return -1;
> > > +	}
> > > +
> > > +	rte_spinlock_lock(&intr_lock);
> > > +
> > > +	ev.events = EPOLLIN | EPOLLPRI;
> > > +	switch (intr_handle.type) {
> > > +	case RTE_INTR_HANDLE_UIO:
> > > +		ev.data.fd = intr_handle.fd;
> > > +		break;
> > > +#ifdef VFIO_PRESENT
> > > +	case RTE_INTR_HANDLE_VFIO_MSIX:
> > > +	case RTE_INTR_HANDLE_VFIO_MSI:
> > > +	case RTE_INTR_HANDLE_VFIO_LEGACY:
> > > +		ev.data.fd = intr_handle.queue_fd[queue_id];
> > > +		break;
> > > +#endif
> > > +	default:
> > > +		rte_spinlock_unlock(&intr_lock);
> > > +		close(pfd);
> > > +		return -1;
> > > +	}
> > > +
> > > +	if (epoll_ctl(pfd, EPOLL_CTL_ADD, ev.data.fd, &ev) < 0) {
> > > +		RTE_LOG(ERR, EAL, "Error adding fd %d epoll_ctl, %s\n",
> > > +			intr_handle.queue_fd[queue_id], strerror(errno));
> > > +	} else
> > > +		numfds++;
> > > +
> > > +	rte_spinlock_unlock(&intr_lock);
> > > +	/* serve the interrupt */
> > > +	eal_intr_handle_rx_interrupts(port_id, pfd, numfds);
> > > +
> > > +	/**
> > > +	* when we return, we need to rebuild the
> > > +	* list of fds to monitor.
> > > +	*/
> > > +	close(pfd);
> > > +
> > > +	return 0;
> > > +}
> > > diff --git a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
> > > index 20e0977..0e5fa76 100644
> > > --- a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
> > > +++ b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
> > > @@ -283,11 +283,21 @@ pci_vfio_setup_interrupts(struct rte_pci_device *dev, int vfio_dev_fd)
> > >
> > >  		dev->intr_handle.fd = fd;
> > >  		dev->intr_handle.vfio_dev_fd = vfio_dev_fd;
> > > -
> > >  		switch (i) {
> > >  		case VFIO_PCI_MSIX_IRQ_INDEX:
> > >  			internal_config.vfio_intr_mode = RTE_INTR_MODE_MSIX;
> > >  			dev->intr_handle.type = RTE_INTR_HANDLE_VFIO_MSIX;
> > > +			for (i = 0; i < VFIO_MAX_QUEUE_ID; i++) {
> > > +				fd = eventfd(0, 0);
> > > +				if (fd < 0) {
> > > +					RTE_LOG(ERR, EAL,
> > > +					"cannot setup eventfd,"
> > > +					"error %i (%s)\n",
> > > +					errno, strerror(errno));
> > > +					return -1;
> > > +				}
> > > +				dev->intr_handle.queue_fd[i] = fd;
> > > +			}
> > >  			break;
> > >  		case VFIO_PCI_MSI_IRQ_INDEX:
> > >  			internal_config.vfio_intr_mode = RTE_INTR_MODE_MSI;
> > > diff --git a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
> > b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
> > > index 23eafd9..c6982cf 100644
> > > --- a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
> > > +++ b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
> > > @@ -38,6 +38,8 @@
> > >  #ifndef _RTE_LINUXAPP_INTERRUPTS_H_
> > >  #define _RTE_LINUXAPP_INTERRUPTS_H_
> > >
> > > +#define VFIO_MAX_QUEUE_ID 32
> > > +
> > >  enum rte_intr_handle_type {
> > >  	RTE_INTR_HANDLE_UNKNOWN = 0,
> > >  	RTE_INTR_HANDLE_UIO,      /**< uio device handle */
> > > @@ -52,6 +54,8 @@ enum rte_intr_handle_type {
> > >  struct rte_intr_handle {
> > >  	int vfio_dev_fd;                 /**< VFIO device file descriptor */
> > >  	int fd;                          /**< file descriptor */
> > > +	int max_intr;                    /**< max interrupt requested */
> > > +	int queue_fd[VFIO_MAX_QUEUE_ID]; /**< rx and tx queue interrupt file descriptor */
> > This is used outside of this library, you need to move these new fields to the
> > end of the structure.
> > 
> > neil
> 
> Alright, I will move them to the end in V4 patch. 
> 
> Neil, do you have any simple writeup on guideline about how to add APIs and new fields to existing 
> structure in order to make sure new stuff does not break ABI? It might help all the developers to avoid
> making similar mistakes in the future.
> 
Not as such, but the ABI document in the release notes gives some examples.  We
can certainly start one if you like, though many of them are situationally
specific. 


> > 
> > >  	enum rte_intr_handle_type type;  /**< handle type */
> > >  };
> > >
> > > --
> > > 1.8.1.4
> > >
> > >
>
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