[dpdk-dev] [PATCH] ethdev: make struct rte_eth_dev cache aligned
Jerin Jacob
jerin.jacob at caviumnetworks.com
Tue May 3 14:10:57 CEST 2016
On Tue, May 03, 2016 at 10:40:53AM +0100, Bruce Richardson wrote:
> On Mon, May 02, 2016 at 01:37:45PM +0530, Jerin Jacob wrote:
> > Elements of struct rte_eth_dev used in the fast path.
> > Make struct rte_eth_dev cache aligned to avoid the cases where
> > rte_eth_dev elements share the same cache line with other structures.
> >
> > Signed-off-by: Jerin Jacob <jerin.jacob at caviumnetworks.com>
> > ---
> > lib/librte_ether/rte_ethdev.c | 2 +-
> > lib/librte_ether/rte_ethdev.h | 2 +-
> > 2 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
> > index a31018e..04f492d 100644
> > --- a/lib/librte_ether/rte_ethdev.c
> > +++ b/lib/librte_ether/rte_ethdev.c
> > @@ -70,7 +70,7 @@
> > #include "rte_ethdev.h"
> >
> > static const char *MZ_RTE_ETH_DEV_DATA = "rte_eth_dev_data";
> > -struct rte_eth_dev rte_eth_devices[RTE_MAX_ETHPORTS];
> > +struct rte_eth_dev rte_eth_devices[RTE_MAX_ETHPORTS] __rte_cache_aligned;
> > static struct rte_eth_dev_data *rte_eth_dev_data;
> > static uint8_t nb_ports;
> >
> > diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
> > index 8519ff6..e359dda 100644
> > --- a/lib/librte_ether/rte_ethdev.h
> > +++ b/lib/librte_ether/rte_ethdev.h
> > @@ -1630,7 +1630,7 @@ struct rte_eth_dev {
> > struct rte_eth_rxtx_callback *pre_tx_burst_cbs[RTE_MAX_QUEUES_PER_PORT];
> > uint8_t attached; /**< Flag indicating the port is attached */
> > enum rte_eth_dev_type dev_type; /**< Flag indicating the device type */
> > -};
> > +} __rte_cache_aligned;
> >
> > struct rte_eth_dev_sriov {
> > uint8_t active; /**< SRIOV is active with 16, 32 or 64 pools */
> > --
> Adding cache aligned in two places is overkill, I think. If the structure is
> marked as being cache aligned, there is no need to have the rte_eth_devices
> marked that way too. I suggest therefore just keeping the structure alignment.
OK. Will fix it in v2
>
> Regards,
> /Bruce
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