[dpdk-dev] [PATCH v1 4/5] eal: add per rx queue interrupt handling based on VFIO

Zhou, Danny danny.zhou at intel.com
Thu Jan 29 05:01:13 CET 2015


Thanks for review Steve. Comments inline.

> -----Original Message-----
> From: Liang, Cunming
> Sent: Thursday, January 29, 2015 2:10 AM
> To: Zhou, Danny; dev at dpdk.org
> Subject: RE: [dpdk-dev] [PATCH v1 4/5] eal: add per rx queue interrupt handling based on VFIO
> 
> 
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Danny Zhou
> > Sent: Wednesday, January 28, 2015 2:51 AM
> > To: dev at dpdk.org
> > Subject: [dpdk-dev] [PATCH v1 4/5] eal: add per rx queue interrupt handling
> > based on VFIO
> >
> > Signed-off-by: Danny Zhou <danny.zhou at intel.com>
> > Signed-off-by: Yong Liu <yong.liu at intel.com>
> > ---
> >  lib/librte_eal/common/include/rte_eal.h            |   9 +
> >  lib/librte_eal/linuxapp/eal/eal_interrupts.c       | 186
> > ++++++++++++++++-----
> >  lib/librte_eal/linuxapp/eal/eal_pci_vfio.c         |  11 +-
> >  .../linuxapp/eal/include/exec-env/rte_interrupts.h |   4 +
> >  4 files changed, 168 insertions(+), 42 deletions(-)
> >
> > diff --git a/lib/librte_eal/common/include/rte_eal.h
> > b/lib/librte_eal/common/include/rte_eal.h
> > index f4ecd2e..5f31aa5 100644
> > --- a/lib/librte_eal/common/include/rte_eal.h
> > +++ b/lib/librte_eal/common/include/rte_eal.h
> > @@ -150,6 +150,15 @@ 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
> > + * @return
> > + *   - On success, return 0
> [LCM] It has changes to return -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/eal_interrupts.c
> > b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
> > index dc2668a..b120303 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 +128,7 @@ static pthread_t intr_thread;
> >  #ifdef VFIO_PRESENT
> >
> >  #define IRQ_SET_BUF_LEN  (sizeof(struct vfio_irq_set) + sizeof(int))
> > +#define MSIX_IRQ_SET_BUF_LEN (sizeof(struct vfio_irq_set) + sizeof(int) *
> > (VFIO_MAX_QUEUE_ID + 1))
> >
> >  /* enable legacy (INTx) interrupts */
> >  static int
> > @@ -221,7 +223,7 @@ vfio_disable_intx(struct rte_intr_handle *intr_handle) {
> >  /* enable MSI-X 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 +232,19 @@ 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);
> >
> > @@ -244,23 +253,6 @@ 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;
> >  }
> >
> > @@ -292,8 +284,8 @@ 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 +293,19 @@ 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 +315,6 @@ 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 +322,7 @@ 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 +807,124 @@ 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 dor 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];
> [LCM] I don't think it's a way to define array by var.

It looks a little bit ugly. The similar implementation in eal_intr_handle_interrupts()
has been there for years. This part of code copied from eal_intr_handle_interrupts().

> 
> > +	int nfds = 0;
> > +
> > +m_wait:
> 
>  [LCM] 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;
> > +	}
> > +	/* epoll_wait timeout, will never happens here */
> [LCM] } while (nfds == 0);
> 
> > +	else if (nfds == 0)
> > +		goto m_wait;
> [LCM] Then we don't need lable 'm_wait' there.

Good suggestion and will take it. There is another "goto m_wait" which 
is removed per other' suggestion. For current control flow, do..while is 
cleaner and better.

> > +	/* 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:
> > +		ev.data.fd = intr_handle.queue_fd[queue_id];
> > +		break;
> > +	case RTE_INTR_HANDLE_VFIO_MSI:
> > +		ev.data.fd = intr_handle.queue_fd[queue_id];
> > +		break;
> > +	case RTE_INTR_HANDLE_VFIO_LEGACY:
> > +		ev.data.fd = intr_handle.queue_fd[queue_id];
> > +		break;
> > +#endif
> > +	default:
> > +		break;
> > +			close(pfd);
> > +			return -1;
> [LCM] It makes confusing here. If directly return, 'break' won't require and need to add unlock.

Good catch, it will be fixed in V2.

> > +	}
> > +
> > +	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..63d0ae8 100644
> > --- a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
> > +++ b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
> > @@ -283,7 +283,6 @@ 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;
> > @@ -302,6 +301,16 @@ pci_vfio_setup_interrupts(struct rte_pci_device *dev,
> > int vfio_dev_fd)
> >  			return -1;
> >  		}
> >
> > +		for (i = 0; i < VFIO_MAX_QUEUE_ID; i++) {
> > +			fd = eventfd(0, 0);
> > +			if (fd < 0) {
> > +				RTE_LOG(ERR, EAL, "  cannot set up eventfd, "
> > +						"error %i (%s)\n", errno, strerror(errno));
> > +				return -1;
> > +			}
> > +			dev->intr_handle.queue_fd[i] = fd;
> > +		}
> > +
> >  		return 0;
> >  	}
> >
> > 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 */
> >  	enum rte_intr_handle_type type;  /**< handle type */
> >  };
> >
> > --
> > 1.8.1.4



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