[ovs-dev] [PATCHv5] netdev-afxdp: Add interrupt mode netdev class.

Ilya Maximets i.maximets at ovn.org
Mon Apr 27 15:56:28 UTC 2020


On 4/27/20 5:54 PM, William Tu wrote:
> On Tue, Apr 14, 2020 at 6:23 AM William Tu <u9012063 at gmail.com> wrote:
>>
>> The patch adds a new netdev class 'afxdp-nonpmd' to enable afxdp
>> interrupt mode. This is similar to 'type=afxdp', except that the
>> is_pmd field is set to false. As a result, the packet processing
>> is handled by main thread, not pmd thread. This avoids burning
>> the CPU to always 100% when there is no traffic.
>>
>> Signed-off-by: William Tu <u9012063 at gmail.com>
>> ---
>> v5:
>>   - add NETDEV_AFXDP_CLASS_COMMON
>> v4:
>>   - Previously crash and fix it with qid = qid % netdev_n_txq(netdev)
>>     Now remove it because Ilya's fix:
>>       "dpif-netdev: Force port reconfiguration to change dynamic_txqs."
>> ---
>>  NEWS                  |  3 +++
>>  lib/netdev-linux.c    | 37 +++++++++++++++++++++++--------------
>>  lib/netdev-provider.h |  1 +
>>  lib/netdev.c          |  1 +
>>  tests/system-afxdp.at | 23 +++++++++++++++++++++++
>>  5 files changed, 51 insertions(+), 14 deletions(-)
>>
>> diff --git a/NEWS b/NEWS
>> index 70bd17584594..6db2d993ffdb 100644
>> --- a/NEWS
>> +++ b/NEWS
>> @@ -10,6 +10,9 @@ Post-v2.13.0
>>       * Deprecated DPDK ring ports (dpdkr) are no longer supported.
>>     - Linux datapath:
>>       * Support for kernel versions up to 5.5.x.
>> +   - AF_XDP:
>> +     * New netdev class 'afxdp-nonpmd' for netdev-afxdp to save CPU cycles
>> +       by enabling interrupt mode.
>>
>>
>>  v2.13.0 - 14 Feb 2020
>> diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
>> index ff045cb1290b..1d7ed0145c48 100644
>> --- a/lib/netdev-linux.c
>> +++ b/lib/netdev-linux.c
>> @@ -3599,24 +3599,33 @@ const struct netdev_class netdev_internal_class = {
>>  };
>>
>>  #ifdef HAVE_AF_XDP
>> +#define NETDEV_AFXDP_CLASS_COMMON                               \
>> +    .construct = netdev_afxdp_construct,                        \
>> +    .destruct = netdev_afxdp_destruct,                          \
>> +    .get_stats = netdev_afxdp_get_stats,                        \
>> +    .get_custom_stats = netdev_afxdp_get_custom_stats,          \
>> +    .get_status = netdev_linux_get_status,                      \
>> +    .set_config = netdev_afxdp_set_config,                      \
>> +    .get_config = netdev_afxdp_get_config,                      \
>> +    .reconfigure = netdev_afxdp_reconfigure,                    \
>> +    .get_numa_id = netdev_linux_get_numa_id,                    \
>> +    .send = netdev_afxdp_batch_send,                            \
>> +    .rxq_construct = netdev_afxdp_rxq_construct,                \
>> +    .rxq_destruct = netdev_afxdp_rxq_destruct,                  \
>> +    .rxq_recv = netdev_afxdp_rxq_recv
>> +
>>  const struct netdev_class netdev_afxdp_class = {
>>      NETDEV_LINUX_CLASS_COMMON,
>> +    NETDEV_AFXDP_CLASS_COMMON,
>>      .type = "afxdp",
>>      .is_pmd = true,
>> -    .init = netdev_afxdp_init,
>> -    .construct = netdev_afxdp_construct,
>> -    .destruct = netdev_afxdp_destruct,
>> -    .get_stats = netdev_afxdp_get_stats,
>> -    .get_custom_stats = netdev_afxdp_get_custom_stats,
>> -    .get_status = netdev_linux_get_status,
>> -    .set_config = netdev_afxdp_set_config,
>> -    .get_config = netdev_afxdp_get_config,
>> -    .reconfigure = netdev_afxdp_reconfigure,
>> -    .get_numa_id = netdev_linux_get_numa_id,
>> -    .send = netdev_afxdp_batch_send,
>> -    .rxq_construct = netdev_afxdp_rxq_construct,
>> -    .rxq_destruct = netdev_afxdp_rxq_destruct,
>> -    .rxq_recv = netdev_afxdp_rxq_recv,
>> +};
>> +
>> +const struct netdev_class netdev_afxdp_nonpmd_class = {
>> +    NETDEV_LINUX_CLASS_COMMON,
>> +    NETDEV_AFXDP_CLASS_COMMON,
>> +    .type = "afxdp-nonpmd",
>> +    .is_pmd = false,
>>  };
>>  #endif
>>
>> diff --git a/lib/netdev-provider.h b/lib/netdev-provider.h
>> index 6f509424bc81..d9503adb0fb6 100644
>> --- a/lib/netdev-provider.h
>> +++ b/lib/netdev-provider.h
>> @@ -850,6 +850,7 @@ extern const struct netdev_class netdev_tap_class;
>>
>>  #ifdef HAVE_AF_XDP
>>  extern const struct netdev_class netdev_afxdp_class;
>> +extern const struct netdev_class netdev_afxdp_nonpmd_class;
>>  #endif
>>  #ifdef  __cplusplus
>>  }
>> diff --git a/lib/netdev.c b/lib/netdev.c
>> index 8c44eee8e98a..90962eec66cf 100644
>> --- a/lib/netdev.c
>> +++ b/lib/netdev.c
>> @@ -154,6 +154,7 @@ netdev_initialize(void)
>>          netdev_register_flow_api_provider(&netdev_offload_tc);
>>  #ifdef HAVE_AF_XDP
>>          netdev_register_provider(&netdev_afxdp_class);
>> +        netdev_register_provider(&netdev_afxdp_nonpmd_class);
>>  #endif
>>  #endif
>>  #if defined(__FreeBSD__) || defined(__NetBSD__)
>> diff --git a/tests/system-afxdp.at b/tests/system-afxdp.at
>> index e4451624f882..0d09906fb6c8 100644
>> --- a/tests/system-afxdp.at
>> +++ b/tests/system-afxdp.at
>> @@ -22,3 +22,26 @@ AT_CHECK([grep "ovs-p0: could not set configuration" ovs-vswitchd.log | wc -l],
>>  OVS_TRAFFIC_VSWITCHD_STOP(["/ovs-p0: Too big 'n_rxq'/d
>>  /ovs-p0: could not set configuration/d"])
>>  AT_CLEANUP
>> +
>> +
>> +AT_SETUP([AF_XDP - ping between pmd and non-pmd ports])
>> +AT_KEYWORDS([afxdp nonpmd])
>> +OVS_TRAFFIC_VSWITCHD_START()
>> +
>> +AT_CHECK([ovs-ofctl add-flow br0 "actions=normal"])
>> +
>> +ADD_NAMESPACES(at_ns0, at_ns1)
>> +ADD_VETH(p0, at_ns0, br0, "10.1.1.1/24")
>> +ADD_VETH(p1, at_ns1, br0, "10.1.1.2/24")
>> +
>> +AT_CHECK([ovs-vsctl del-port ovs-p0])
>> +AT_CHECK([ovs-vsctl add-port br0 ovs-p0 -- \
>> +                    set interface ovs-p0 type=afxdp-nonpmd options:n_rxq=1],
>> +         [0], [], [stderr])
>> +
>> +NS_CHECK_EXEC([at_ns0], [ping -q -c 3 -i 0.3 -w 2 10.1.1.2 | FORMAT_PING], [0], [dnl
>> +3 packets transmitted, 3 received, 0% packet loss, time 0ms
>> +])
>> +
>> +OVS_TRAFFIC_VSWITCHD_STOP
>> +AT_CLEANUP
>> --
>> 2.7.4
>>
> Hi Ilya,
> Do you think this version looks good?

I actually had a plan to check it a bit later today.

Best regards, Ilya Maximets.


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