packet drop
Hi All, I am sending packet between two back to back connected machine.when I use same network (192.168.7.x) packet reach upto NF_IP_LOCAL_IN (IPTABLES INPUT) hook.It is accepted. But when I spoof ip address network(192.168.8.x) it pass NF_IP_PRE_ROUTING hook but dropped before NF_IP_LOCAL_IN hook. case 1: 192.168.7.12 --> 192.168.7.19 Accepted. case 2: 192.168.8.25 --> 192.168.7.19 Dropped. I didn't get why it dropped ? How network change effect on routing inside kernel tcp/ip stack ? Regards Varun ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: How to avoid packet drop
> I am running a tool that is a packet generator. > With that tool i am able to achieve line/link rate on my 1Gbps network. > I have two queries > > Query 1) When i run the same tool on 10Gbps network i am able to achieve > only 5Gbps rate.( by network i mean i have two machines with Centos 6.4 > connected back to back.) > If your question is why you are not able to get line rate on 10 Gb interface, try faster machines. Dell T110 can do line rate easily and Dell T620 can do 2 line rates (for 10 Gb) simultaneously Query 2) When i run the packet generator on the 1Gbps link or 10Gbps link i > see a packet drop by kernel ( result of tcpdump -i eth2).How can i minimize > the packet drop? > If you are referring to packet drop by tcpdump (when you ctrl-c it), this packet is not dropped by kernel stack, but by tcpdump filter. For packets dropped by stack you can look at sats in /proc or look in ifconfig for packets dropped by the hardware. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
How to avoid packet drop
Hi All, I am running a tool that is a packet generator. With that tool i am able to achieve line/link rate on my 1Gbps network. I have two queries Query 1) When i run the same tool on 10Gbps network i am able to achieve only 5Gbps rate.( by network i mean i have two machines with Centos 6.4 connected back to back.) Query 2) When i run the packet generator on the 1Gbps link or 10Gbps link i see a packet drop by kernel ( result of tcpdump -i eth2).How can i minimize the packet drop? Thanks Clove ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Re: Packet drop while using BPF filter
* On Sat, Dec 24, 2011 at 09:57:50PM +0530, Mukesh Yadav wrote: Hi Raghavendra, " /proc/sys/net/core/bpf_jit_**enable " is not present on machine. Seems kernel need to be configured for these. Yes, it is a fairly new option -- CONFIG_BPF_JIT=y Btw CPU scaling issue is resolved. Packet drop was because all interrupt handling was happening on core where packets were getting drop. Tuning system for interrupt handling using smp_affinity resolved the issue. That is generally how it is done. The core which handles packets initially handles the interrupts too. Do you mean all non-network interrupts were happening on same core ? Then give irqbalance a shot. Thanks Mukesh On 22 December 2011 19:18, Raghavendra D Prabhu wrote: Hi, Have you tried enabling -- /proc/sys/net/core/bpf_jit_**enable -- provides JIT compiled BPF on 64 bit linux. * On Wed, Dec 21, 2011 at 12:08:04AM +0530, Mukesh Yadav < mukesh@gmail.com> wrote: Hi Guys, I am working on user level code which uses BPF filter. Solution has two threads and BPF filter for incoming packets to raw socket dedicated to each thread. Intent is to divide ingress traffic between two thread based on whether dest IP is even or odd. BPF filters used are: Even IP filter :-> tcpdump -i interface 'ether dst && ip[19] & 0x01 = 0' Odd IP filter :-> tcpdump -i interface 'ether dst && ip[19] & 0x01 = 1' There is a packet loss for odd IP thread even when CPU is available. Reason being packet drop due recv buffer full. Same amount of traffic is well handled by even IP thread(user code being same in both), scaling CPU to full 100%. In odd IP thread, If filter is changed to "tcpdump -i interface 'ether dst && ip proto 17' ", all goes fine. Also CPU usage at kernel drops from 50% to 4 % for a particular amount of traffic. Would appreciate any I/ps for reducing load at kernel for packet filtering(Odd/Even IP distribution) Cheers Mukesh __**_ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.**org http://lists.kernelnewbies.**org/mailman/listinfo/**kernelnewbies<http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies> -- Raghavendra Prabhu GPG Id : 0xD72BE977 Fingerprint: B93F EBCB 8E05 7039 CD3C A4B8 A616 DCA1 D72B E977 www: wnohang.net pgpEXJTG0gMUn.pgp Description: PGP signature ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Packet drop while using BPF filter
Hi Raghavendra, " /proc/sys/net/core/bpf_jit_**enable " is not present on machine. Seems kernel need to be configured for these. Btw CPU scaling issue is resolved. Packet drop was because all interrupt handling was happening on core where packets were getting drop. Tuning system for interrupt handling using smp_affinity resolved the issue. Thanks Mukesh On 22 December 2011 19:18, Raghavendra D Prabhu wrote: > Hi, > >Have you tried enabling -- /proc/sys/net/core/bpf_jit_**enable -- >provides JIT compiled BPF on 64 bit linux. > > > * On Wed, Dec 21, 2011 at 12:08:04AM +0530, Mukesh Yadav < > mukesh@gmail.com> wrote: > >> Hi Guys, >> >> I am working on user level code which uses BPF filter. >> Solution has two threads and BPF filter for incoming packets to raw >> socket >> dedicated to each thread. >> Intent is to divide ingress traffic between two thread based on whether >> dest IP is even or odd. >> >> BPF filters used are: >> Even IP filter :-> tcpdump -i interface 'ether dst && ip[19] & >> 0x01 = 0' >> Odd IP filter :-> tcpdump -i interface 'ether dst && ip[19] & >> 0x01 = 1' >> >> There is a packet loss for odd IP thread even when CPU is available. >> Reason >> being packet drop due recv buffer full. >> Same amount of traffic is well handled by even IP thread(user code being >> same in both), scaling CPU to full 100%. >> >> In odd IP thread, If filter is changed to "tcpdump -i interface 'ether >> dst >> && ip proto 17' ", all goes fine. >> Also CPU usage at kernel drops from 50% to 4 % for a particular amount of >> traffic. >> >> Would appreciate any I/ps for reducing load at kernel for packet >> filtering(Odd/Even IP distribution) >> >> >> Cheers >> Mukesh >> > > __**_ >> Kernelnewbies mailing list >> Kernelnewbies@kernelnewbies.**org >> http://lists.kernelnewbies.**org/mailman/listinfo/**kernelnewbies<http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies> >> > > -- > Raghavendra Prabhu > GPG Id : 0xD72BE977 > Fingerprint: B93F EBCB 8E05 7039 CD3C A4B8 A616 DCA1 D72B E977 > www: wnohang.net > -- Cheers Mukesh Yadav Senior Software Engineer Plot6 Sector 18 Aricent Gurgaon Mob: 9953024169 ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Packet drop while using BPF filter
Hi, Have you tried enabling -- /proc/sys/net/core/bpf_jit_enable -- provides JIT compiled BPF on 64 bit linux. * On Wed, Dec 21, 2011 at 12:08:04AM +0530, Mukesh Yadav wrote: >Hi Guys, > >I am working on user level code which uses BPF filter. >Solution has two threads and BPF filter for incoming packets to raw socket >dedicated to each thread. >Intent is to divide ingress traffic between two thread based on whether >dest IP is even or odd. > >BPF filters used are: >Even IP filter :-> tcpdump -i interface 'ether dst && ip[19] & >0x01 = 0' >Odd IP filter :-> tcpdump -i interface 'ether dst && ip[19] & >0x01 = 1' > >There is a packet loss for odd IP thread even when CPU is available. Reason >being packet drop due recv buffer full. >Same amount of traffic is well handled by even IP thread(user code being >same in both), scaling CPU to full 100%. > >In odd IP thread, If filter is changed to "tcpdump -i interface 'ether dst > && ip proto 17' ", all goes fine. >Also CPU usage at kernel drops from 50% to 4 % for a particular amount of >traffic. > >Would appreciate any I/ps for reducing load at kernel for packet >filtering(Odd/Even IP distribution) > > >Cheers >Mukesh >___ >Kernelnewbies mailing list >Kernelnewbies@kernelnewbies.org >http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies -- Raghavendra Prabhu GPG Id : 0xD72BE977 Fingerprint: B93F EBCB 8E05 7039 CD3C A4B8 A616 DCA1 D72B E977 www: wnohang.net ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Packet drop while using BPF filter
Hi Mukesh On Wed, Dec 21, 2011 at 12:25, Mukesh Yadav wrote: > Thanks Mulyadi, > Yeah that a final alternative. Actually I was looking for some optimized > way of getting packet filtered at kernel level using BPF filter. You're welcome. Logically, your code should have no problem, but well it seems that the implementation in BPF is not so good somewhere. -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Packet drop while using BPF filter
Thanks Mulyadi, Yeah that a final alternative. Actually I was looking for some optimized way of getting packet filtered at kernel level using BPF filter. On 21 December 2011 06:22, Mulyadi Santosa wrote: > Hi Mukesh.. > > On Wed, Dec 21, 2011 at 01:38, Mukesh Yadav wrote: > > BPF filters used are: > > Even IP filter :-> tcpdump -i interface 'ether dst && ip[19] & > > 0x01 = 0' > > Odd IP filter :-> tcpdump -i interface 'ether dst && ip[19] > & > > 0x01 = 1' > > > > There is a packet loss for odd IP thread even when CPU is available. > Reason > > being packet drop due recv buffer full. > > Same amount of traffic is well handled by even IP thread(user code being > > same in both), scaling CPU to full 100%. > > > > In odd IP thread, If filter is changed to "tcpdump -i interface 'ether > dst > > && ip proto 17' ", all goes fine. > > Also CPU usage at kernel drops from 50% to 4 % for a particular amount of > > traffic. > > I have zero experience with BPF, so this is just my theory. > > In kernel level, (or maybe between kernel and user level), by putting > your odd and even filter, kernel work too hard to separate the packets > into different "queue" or "channel"...or something like that. While in > the mean time, incoming packets are bursting This makes buffers > filled up fast. > > How about this... just filter anything that match your target > MACfed this up to the user level application and let your > application do the odd and even IP filtering? > > -- > regards, > > Mulyadi Santosa > Freelance Linux trainer and consultant > > blog: the-hydra.blogspot.com > training: mulyaditraining.blogspot.com > -- Cheers Mukesh Yadav Senior Software Engineer Plot6 Sector 18 Aricent Gurgaon Mob: 9953024169 ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Packet drop while using BPF filter
Hi Mukesh.. On Wed, Dec 21, 2011 at 01:38, Mukesh Yadav wrote: > BPF filters used are: > Even IP filter :-> tcpdump -i interface 'ether dst && ip[19] & > 0x01 = 0' > Odd IP filter :-> tcpdump -i interface 'ether dst && ip[19] & > 0x01 = 1' > > There is a packet loss for odd IP thread even when CPU is available. Reason > being packet drop due recv buffer full. > Same amount of traffic is well handled by even IP thread(user code being > same in both), scaling CPU to full 100%. > > In odd IP thread, If filter is changed to "tcpdump -i interface 'ether dst > && ip proto 17' ", all goes fine. > Also CPU usage at kernel drops from 50% to 4 % for a particular amount of > traffic. I have zero experience with BPF, so this is just my theory. In kernel level, (or maybe between kernel and user level), by putting your odd and even filter, kernel work too hard to separate the packets into different "queue" or "channel"...or something like that. While in the mean time, incoming packets are bursting This makes buffers filled up fast. How about this... just filter anything that match your target MACfed this up to the user level application and let your application do the odd and even IP filtering? -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Packet drop while using BPF filter
Hi Guys, I am working on user level code which uses BPF filter. Solution has two threads and BPF filter for incoming packets to raw socket dedicated to each thread. Intent is to divide ingress traffic between two thread based on whether dest IP is even or odd. BPF filters used are: Even IP filter :-> tcpdump -i interface 'ether dst && ip[19] & 0x01 = 0' Odd IP filter :-> tcpdump -i interface 'ether dst && ip[19] & 0x01 = 1' There is a packet loss for odd IP thread even when CPU is available. Reason being packet drop due recv buffer full. Same amount of traffic is well handled by even IP thread(user code being same in both), scaling CPU to full 100%. In odd IP thread, If filter is changed to "tcpdump -i interface 'ether dst && ip proto 17' ", all goes fine. Also CPU usage at kernel drops from 50% to 4 % for a particular amount of traffic. Would appreciate any I/ps for reducing load at kernel for packet filtering(Odd/Even IP distribution) Cheers Mukesh ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
