On 9/19/20 3:07 PM, Flavio Leitner wrote: > The EMC is not large enough for current production cases > and they are scaling up, so this change switches over from > EMC to SMC by default, which provides better results. > > The EMC is still available and could be used when only a > few number of flows is used. >
Hi, Flavio. Thanks for the patch! I generally agree with this change. The main thing that bothers me is that with current version of the patch we will drop all testing on EMC at once. Right now EMC is enabled by default, so we have it tested in many cases. We also have probability configuration covered in one test. And we have at least one test with SMC enabled. We doesn't check SMC hits, but at least insertions should work. :) After this patch we will have zero tests with EMC enabled. And that is not a good thing. In general, I think that we need much more tests for both SMC and EMC, but at least couple of tests needed for EMC right now since you're disabling it by default. And we definitely need at least one test for emc-insert-inv-prob configuration. One more thing is that our DPCLS implementation could actually be faster than SMC in some cases [1], so, I think, maybe it worth performing a series of performance tests to better understand what we actually want. It may turn out that we want to disable all the caches by default and just have datapath classifier to handle all the traffic since it's more flexible and even faster in common cases. [1] https://mail.openvswitch.org/pipermail/ovs-dev/2019-July/360586.html Few minor comments inline. Best regards, Ilya Maximets. > Signed-off-by: Flavio Leitner <f...@sysclose.org> > --- > Documentation/topics/dpdk/bridge.rst | 10 +++++----- > NEWS | 3 +++ > lib/dpif-netdev.c | 6 +++--- > tests/pmd.at | 4 ++-- > vswitchd/vswitch.xml | 4 ++-- > 5 files changed, 15 insertions(+), 12 deletions(-) > > diff --git a/Documentation/topics/dpdk/bridge.rst > b/Documentation/topics/dpdk/bridge.rst > index 526d5c959..0d9aed4eb 100644 > --- a/Documentation/topics/dpdk/bridge.rst > +++ b/Documentation/topics/dpdk/bridge.rst > @@ -130,13 +130,13 @@ SMC cache > SMC cache or signature match cache is a new cache level after EMC cache. > The difference between SMC and EMC is SMC only stores a signature of a flow > thus it is much more memory efficient. With same memory space, EMC can store > 8k > -flows while SMC can store 1M flows. When traffic flow count is much larger > than > -EMC size, it is generally beneficial to turn off EMC and turn on SMC. It is > -currently turned off by default. > +flows while SMC can store 1M flows. When traffic flow count is small than > +EMC size, it is generally beneficial to turn off SMC and turn on EMC. It is > +currently turned on by default. > > -To turn on SMC:: > +To turn off SMC:: > > - $ ovs-vsctl --no-wait set Open_vSwitch . other_config:smc-enable=true > + $ ovs-vsctl --no-wait set Open_vSwitch . other_config:smc-enable=false > > Datapath Classifier Performance > ------------------------------- > diff --git a/NEWS b/NEWS > index 2f67d5047..5b88937fb 100644 > --- a/NEWS > +++ b/NEWS > @@ -1,6 +1,9 @@ > Post-v2.14.0 > --------------------- > Usually, we do not have an empty line here. > + - DPDK: This should say "Userspace datapath:" instead, as this is a generic change for all port types. > + * The SMC cache is enabled by default. > + * The EMC cache is disabled by default. > > v2.14.0 - 17 Aug 2020 > --------------------- > diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c > index 02df8f11e..0f2bb10fd 100644 > --- a/lib/dpif-netdev.c > +++ b/lib/dpif-netdev.c > @@ -2079,7 +2079,7 @@ port_create(const char *devname, const char *type, > port->netdev = netdev; > port->type = xstrdup(type); > port->sf = NULL; > - port->emc_enabled = true; > + port->emc_enabled = false; > port->need_reconfigure = true; > ovs_mutex_init(&port->txq_used_mutex); > > @@ -4305,7 +4305,7 @@ dpif_netdev_set_config(struct dpif *dpif, const struct > smap *other_config) > } > } > > - bool smc_enable = smap_get_bool(other_config, "smc-enable", false); > + bool smc_enable = smap_get_bool(other_config, "smc-enable", true); > bool cur_smc; > atomic_read_relaxed(&dp->smc_enable_db, &cur_smc); > if (smc_enable != cur_smc) { > @@ -4440,7 +4440,7 @@ dpif_netdev_port_set_config(struct dpif *dpif, > odp_port_t port_no, > struct dp_netdev_port *port; > int error = 0; > const char *affinity_list = smap_get(cfg, "pmd-rxq-affinity"); > - bool emc_enabled = smap_get_bool(cfg, "emc-enable", true); > + bool emc_enabled = smap_get_bool(cfg, "emc-enable", false); > > ovs_mutex_lock(&dp->port_mutex); > error = get_port_by_number(dp, port_no, &port); > diff --git a/tests/pmd.at b/tests/pmd.at > index 5b612f88f..20c179b39 100644 > --- a/tests/pmd.at > +++ b/tests/pmd.at > @@ -238,8 +238,8 @@ pmd thread numa_id <cleared> core_id <cleared>: > packets received: 20 > packet recirculations: 0 > avg. datapath passes per packet: 1.00 > - emc hits: 19 > - smc hits: 0 > + emc hits: 0 > + smc hits: 19 > megaflow hits: 0 > avg. subtable lookups per megaflow hit: 0.00 > miss with success upcall: 1 > diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml > index 81c84927f..009f0e550 100644 > --- a/vswitchd/vswitch.xml > +++ b/vswitchd/vswitch.xml > @@ -513,7 +513,7 @@ > when flow count is larger than EMC capacity. > </p> > <p> > - Defaults to false but can be changed at any time. > + Defaults to true but can be changed at any time. > </p> > </column> > > @@ -3296,7 +3296,7 @@ ovs-vsctl add-port br0 p0 -- set Interface p0 > type=patch options:peer=p1 \ > key="emc-insert-inv-prob"/> will have effect on this interface. > </p> > <p> > - Defaults to true. > + Defaults to false. > </p> > </column> > </group> > _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
