Heavy network loading...

Brad Fitzpatrick brad at danga.com
Tue Sep 5 23:03:41 UTC 2006


Which memcached version?

(wondering because of sendmsg)


On Tue, 5 Sep 2006, Tim Yardley wrote:

> All;
>
> Since a lot of us here run machines with high traffic loads, I hope this is
> relatively on-topic.  I have an interesting situation in which a box is
> "heavily" loaded with network traffic on a bridged interface.  The loading
> isn't directly related to memcached, but I figured someone here might have
> run into this before based on stress testing memcache or just from high load
> sites.
>
> During the heavy load I get the following situation:
>
> # ping -n google.com
> PING google.com (64.233.167.99) 56(84) bytes of data.
> ping: sendmsg: Operation not permitted
> ping: sendmsg: Operation not permitted
> ping: sendmsg: Operation not permitted
> ping: sendmsg: Operation not permitted
> ping: sendmsg: Operation not permitted
> ping: sendmsg: Operation not permitted
> 64 bytes from 64.233.167.99: icmp_seq=6 ttl=242 time=1023 ms
> 64 bytes from 64.233.167.99: icmp_seq=8 ttl=242 time=22.8 ms
> 64 bytes from 64.233.167.99: icmp_seq=9 ttl=242 time=22.0 ms
> ping: sendmsg: Operation not permitted
>
> Snip of the strace:
>
> --------
>
> sendmsg(3, {msg_name(16)={sa_family=AF_INET, sin_port=htons(0),
> sin_addr=inet_addr("64.233.167.99")},
> msg_iov(1)=[{"\10\0\211\321\225h\0m/\373\375D\270\25\10\0\10\t\n\v\f"...,
> 64}], msg_controllen=0, msg_flags=0}, MSG_CONFIRM) = -1 EPERM (Operation not
> permitted)
> recvmsg(3, 0xbfe96470, MSG_ERRQUEUE|MSG_DONTWAIT) = -1 EAGAIN (Resource
> temporarily unavailable)
> dup(2)                                  = 4
> fcntl64(4, F_GETFL)                     = 0x2 (flags O_RDWR)
> fstat64(4, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 5), ...}) = 0
> mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
> 0xb7e44000
> _llseek(4, 0, 0xbfe96540, SEEK_CUR)     = -1 ESPIPE (Illegal seek)
> write(4, "ping: sendmsg: Operation not per"..., 39) = 39
> close(4)                                = 0
> munmap(0xb7e44000, 4096)                = 0
> recvmsg(3, 0xbfe96710, 0)               = -1 EAGAIN (Resource temporarily
> unavailable)
> gettimeofday({1157495600, 551997}, NULL) = 0
> gettimeofday({1157495600, 552181}, NULL) = 0
> sendmsg(3, {msg_name(16)={sa_family=AF_INET, sin_port=htons(0),
> sin_addr=inet_addr("64.233.167.99")},
> msg_iov(1)=[{"\10\0Ky\225h\0n0\373\375D\365l\10\0\10\t\n\v\f\r\16\17"...,
> 64}], msg_controllen=0, msg_flags=0}, 0) = 64
> recvmsg(3, {msg_name(16)={sa_family=AF_INET, sin_port=htons(22759),
> sin_addr=inet_addr("64.233.167.99")},
> msg_iov(1)=[{"E\0\0T\0m@\0\363\1\0165@\351\247cD\264L\6\0\0Sy\225h\0"...,
> 192}], msg_controllen=20, {cmsg_len=20, cmsg_level=SOL_SOCKET,
> cmsg_type=0x1d /* SCM_??? */, ...}, msg_flags=0}, 0) = 84
> write(1, "64 bytes from 64.233.167.99: icm"..., 63) = 63
> gettimeofday({1157495600, 580525}, NULL) = 0
> poll([{fd=3, events=POLLIN|POLLERR, revents=POLLIN}], 1, 972) = 1
> recvmsg(3, {msg_name(16)={sa_family=AF_INET, sin_port=htons(46027),
> sin_addr=inet_addr("68.180.76.6")},
> msg_iov(1)=[{"E\300\0XaI\0\0@\1\367\'D\264L\6D\264L\6\3\1\34\303\0\0"...,
> 192}], msg_controllen=20, {cmsg_len=20, cmsg_level=SOL_SOCKET,
> cmsg_type=0x1d /* SCM_??? */, ...}, msg_flags=0}, MSG_DONTWAIT) = 88
> gettimeofday({1157495600, 851056}, NULL) = 0
>
> ----------------
>
> Sysctl.conf:
> net.ipv4.conf.default.rp_filter = 1
> net.ipv4.conf.all.rp_filter = 1
> kernel.sysrq=1
> net.ipv4.ip_forward=1
> kernel.sem=250 32000 100 128
> # Adjust where the gc will leave arp table alone
> net.ipv4.neigh.default.gc_thresh1=256
> net.ipv4.neigh.default.gc_thresh2=1024
> net.ipv4.neigh.default.gc_thresh3=2048
> # Increase TCP
> net.ipv4.neigh.default.proxy_qlen = 96
> net.ipv4.neigh.default.unres_qlen = 6
> # Increase size of socket buffers
> net.ipv4.tcp_rmem = 4096 98304 349520
> net.ipv4.tcp_wmem = 4096 65535 262142
> net.ipv4.tcp_mem = 98304 262142 393216
> # Bump up TCP socket queue mechanism to help with syn floods
> net.ipv4.tcp_max_syn_backlog = 2048
> # Drop it so lack of FIN times out quicker
> net.ipv4.tcp_fin_timeout = 30
> # Increase number of incoming connections backlog
> net.core.somaxconn = 512
> # Bump optmem_max up
> net.core.optmem_max = 20480
> # Increase number of incoming connections backlog
> net.core.netdev_max_backlog = 1024
> # Bump up default r/wmem to max
> net.core.rmem_default = 262141
> net.core.wmem_default = 262141
> # Bump up max r/wmem
> net.core.rmem_max = 262141
> net.core.wmem_max = 262141
> # Increase size of file handles and inode cache
> fs.file-max = 209708
>
> -----------------
>
> Some proc relevance (eth1 and eth2 are the devices pushing the traffic):
>
> # cat /proc/interrupts
>            CPU0       CPU1
>   0:  350401618          0    IO-APIC-edge  timer
>   9:          0          0   IO-APIC-level  acpi
>  14:   15736294          0    IO-APIC-edge  libata
>  15:          0          0    IO-APIC-edge  libata
> 169:          0          0   IO-APIC-level  uhci_hcd:usb2
> 177: 1557943765          0   IO-APIC-level  uhci_hcd:usb3, eth0, eth2
> 185:         41          0   IO-APIC-level  HDA Intel, uhci_hcd:usb4
> 193:          0          0   IO-APIC-level  uhci_hcd:usb1, ehci_hcd:usb5
> 201: 1316369138          0   IO-APIC-level  eth1
> NMI:          0          0
> LOC:  349727026  349727025
> ERR:          0
> MIS:          0
>
> # cat /proc/loadavg
> 1.33 0.90 1.16 2/159 28533
>
> # cat /proc/version
> Linux version 2.6.12-gentoo-r10 (root at meepmeep) (gcc version 3.3.5-20050130
> (Gentoo 3.3.5.20050130-r1, ssp-3.3.5.20050130-1, pie-8.7.7.1)) #4 SMP Sun
> Mar 26 23:00:57 CST 2006
>
> Anyone have any ideas as to what this might be?  Interrupt overload?  Any
> way to relieve this situation?  I've searched around but haven't found much
> definitive.  Linux kernel tuning (2.6.x) websites would be appreciated if
> any of you know of good ones.
>
> Any help is definitely appreciated.  Sysctl tweaks are very much welcome as
> well.  If this is too off-topic for the list, feel free to just reply
> directly.  Thanks in advance.
>
> /tmy
>
>


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