It's documented, see ovs-vswitchd.conf.db(5). On Sat, Jul 25, 2015 at 06:58:09PM -0700, Xuemei Liu wrote: > This is the thread information for ovs-vswitchd, I test with different > traffic rate, the number of threads for ovs-vswitchd is already 11, > including 5 handler threads (should be the threads handling userspace > upcalls). How can I increase the number of handler threads? > [image: Inline image 1] > > Thanks, > Xuemei > > > On Sat, Jul 25, 2015 at 6:15 PM, Xuemei Liu <[email protected]> wrote: > > > Hi, all, > > > > Following Ben's advice, I can forward all packets from kernel space to > > userspace. However, the performance of handling packets in userspace is not > > good enough. I read the code and find threads are used to handle the > > userspace upcalls (in ofproto/ofproto-dpif-upcall.c, function > > udpif_set_thread() ). According to the code, the number of threads should > > be adjustable. What I track from the code is shown below (in bridge.c), but > > I don't know where to set the number of threads. Could you give me some > > hint if possible? > > [image: Inline image 1] > > > > Thanks, > > Xuemei > > > > On Fri, Jul 24, 2015 at 1:24 PM, Ben Pfaff <[email protected]> wrote: > > > >> It doesn't sound like you have a bottleneck, if CPU is less than 10%, so > >> I don't understand the question. > >> > >> On Fri, Jul 24, 2015 at 09:42:05AM -0700, Xuemei Liu wrote: > >> > Hi, Ben, > >> > > >> > I have one follow-up question. I setup a topology with 12 hosts and 12 > >> > switches in Mininet. The hosts (acting as the packets generator to the > >> > network) should send packets around 30 pps in order to make the switches > >> > not drop packets. However, I find that the CPU/MEM usage of > >> ovs-vswitchd is > >> > not high (both < 10%). According to your experience, where do you think > >> is > >> > the bottleneck? How can I improve the performance of packet processing > >> > speed in userspace in Mininet? > >> > > >> > Thanks, > >> > Xuemei > >> > > >> > On Fri, Jul 24, 2015 at 9:30 AM, Xuemei Liu <[email protected]> > >> wrote: > >> > > >> > > Thanks very much Ben. > >> > > > >> > > On Fri, Jul 24, 2015 at 9:25 AM, Ben Pfaff <[email protected]> wrote: > >> > > > >> > >> Any SLOW_* constant indicates why a packet can't be processed in the > >> > >> fast path (e.g. in the kernel). Such packets always have to be > >> handled > >> > >> in userspace. Thus, tagging all flow translations with any SLOW_* > >> > >> constant causes them all to be sent to userspace. > >> > >> > >> > >> On Thu, Jul 23, 2015 at 05:07:58PM -0700, Xuemei Liu wrote: > >> > >> > Hi, Ben, > >> > >> > > >> > >> > After I decreased the sending rate at h1, I find s1 userspace/h2 > >> can > >> > >> > receive all packets. What does SLOW_ACTION mean? Why this will > >> make the > >> > >> > packets forwarded from kernel space to user space? > >> > >> > > >> > >> > Thanks, > >> > >> > Xuemei > >> > >> > > >> > >> > On Thu, Jul 23, 2015 at 4:46 PM, Ben Pfaff <[email protected]> wrote: > >> > >> > > >> > >> > > Well, yes, there are performance problems, as I predicted. > >> > >> > > > >> > >> > > On Thu, Jul 23, 2015 at 04:42:17PM -0700, Xuemei Liu wrote: > >> > >> > > > Let me try to describe it. Suppose the topology is h1-s1-h2, > >> where > >> > >> h1, h2 > >> > >> > > > are hosts, and s1 is the ovs switch. I add policy in s1 to > >> forward > >> > >> > > packets > >> > >> > > > with dstip of h2 to h2. Then I test in two scenarios. > >> > >> > > > 1. h1 sends 9 packets (3 packet for each of 3 different flows) > >> to > >> > >> h2. > >> > >> > > With > >> > >> > > > your methods, userspace in s1 can accept all the packets, and > >> h2 can > >> > >> > > > receive all the 9 packets. Work perfect. > >> > >> > > > 2. h1 sends 10000 packets to h2. In this case, h2 receives the > >> same > >> > >> > > packets > >> > >> > > > as userspace in s1 does. However, the number of packets > >> received is > >> > >> much > >> > >> > > > less than 10000. Which means many packets are lost in s1. > >> > >> > > > Is this clear now? > >> > >> > > > > >> > >> > > > Thanks, > >> > >> > > > Xuemei > >> > >> > > > > >> > >> > > > On Thu, Jul 23, 2015 at 4:18 PM, Ben Pfaff <[email protected]> > >> wrote: > >> > >> > > > > >> > >> > > > > That's too vague for me to guess. What packets are getting > >> lost? > >> > >> > > > > > >> > >> > > > > On Thu, Jul 23, 2015 at 04:10:14PM -0700, Xuemei Liu wrote: > >> > >> > > > > > Hi, Ben, > >> > >> > > > > > > >> > >> > > > > > I tried your method, but the switch seems to drop some > >> packets, > >> > >> as it > >> > >> > > > > does > >> > >> > > > > > not output the expected packets that I forward to send to > >> it. > >> > >> Any > >> > >> > > advice? > >> > >> > > > > > > >> > >> > > > > > Thanks, > >> > >> > > > > > Xuemei > >> > >> > > > > > > >> > >> > > > > > On Thu, Jul 23, 2015 at 10:19 AM, Xuemei Liu < > >> > >> [email protected]> > >> > >> > > > > wrote: > >> > >> > > > > > > >> > >> > > > > > > Hi, Ben, > >> > >> > > > > > > > >> > >> > > > > > > Thanks for your response. > >> > >> > > > > > > "You realize that this will be terrible for performance, > >> > >> right?" > >> > >> > > > > > > In fact, I have not got all packets sent to user space. > >> That > >> > >> is the > >> > >> > > > > > > problem I am facing now. I think performance might be > >> another > >> > >> > > problem > >> > >> > > > > after > >> > >> > > > > > > I can receive all packet in user space. > >> > >> > > > > > > > >> > >> > > > > > > Thanks, > >> > >> > > > > > > Xuemei > >> > >> > > > > > > > >> > >> > > > > > > On Thu, Jul 23, 2015 at 10:13 AM, Ben Pfaff < > >> [email protected]> > >> > >> > >> > >> > > wrote: > >> > >> > > > > > > > >> > >> > > > > > >> On Thu, Jul 23, 2015 at 10:04:23AM -0700, Xuemei Liu > >> wrote: > >> > >> > > > > > >> > I am new to ovs, and I am trying to send all packets > >> from > >> > >> kernel > >> > >> > > > > space > >> > >> > > > > > >> to > >> > >> > > > > > >> > user space. I comment the "unlikely(!flow)" in > >> > >> > > datapath/datapath.c. > >> > >> > > > > > >> > However, it seems I just receive the first packet of > >> each > >> > >> flow > >> > >> > > (the > >> > >> > > > > > >> first > >> > >> > > > > > >> > packet that match one forwarding rule in the bridge) > >> in > >> > >> user > >> > >> > > space. > >> > >> > > > > > >> Could > >> > >> > > > > > >> > anyone tell me why? and is there other way to achieve > >> my > >> > >> goal? > >> > >> > > > > > >> > >> > >> > > > > > >> You realize that this will be terrible for performance, > >> > >> right? > >> > >> > > > > > >> > >> > >> > > > > > >> It's kind of a waste to modify the kernel module for > >> this. > >> > >> I'd > >> > >> > > just > >> > >> > > > > > >> modify userspace to send all packets to userspace, > >> something > >> > >> like > >> > >> > > > > this: > >> > >> > > > > > >> > >> > >> > > > > > >> diff --git a/ofproto/ofproto-dpif-xlate.c > >> > >> > > > > b/ofproto/ofproto-dpif-xlate.c > >> > >> > > > > > >> index 52395a7..a98406a 100644 > >> > >> > > > > > >> --- a/ofproto/ofproto-dpif-xlate.c > >> > >> > > > > > >> +++ b/ofproto/ofproto-dpif-xlate.c > >> > >> > > > > > >> @@ -4777,7 +4777,7 @@ xlate_actions(struct xlate_in > >> *xin, > >> > >> struct > >> > >> > > > > > >> xlate_out *xout) > >> > >> > > > > > >> > >> > >> > > > > > >> ctx.xin = xin; > >> > >> > > > > > >> ctx.xout = xout; > >> > >> > > > > > >> - ctx.xout->slow = 0; > >> > >> > > > > > >> + ctx.xout->slow = SLOW_ACTION; > >> > >> > > > > > >> ctx.xout->has_learn = false; > >> > >> > > > > > >> ctx.xout->has_normal = false; > >> > >> > > > > > >> ctx.xout->has_fin_timeout = false; > >> > >> > > > > > >> > >> > >> > > > > > > > >> > >> > > > > > > > >> > >> > > > > > >> > >> > > > >> > >> > >> > > > >> > > > >> > > > >
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