2.4.x latency
I'm experiencing an odd behavior under the 2.4.0 and 2.4.1 kernels on two of my servers. I'm experiencing high latency periods. Sometimes the periods are long and other times they are short. As a test I setup three ping processes on one of the servers all pinging the same destination on the LAN at the same time. Below is a sample of the ping output. The strange thing is that while all three ping processes went through the latency cycle, they each did it at different times. This tells me that surely this isn't a network response issue or else all ping processes would show the latency at the same time. 64 bytes from (216.185.106.18): icmp_seq=55 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=56 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=57 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=58 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=59 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=60 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=61 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=62 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=63 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=64 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=65 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=66 ttl=255 time=4121.7 ms 64 bytes from (216.185.106.18): icmp_seq=67 ttl=255 time=3259.0 ms 64 bytes from (216.185.106.18): icmp_seq=68 ttl=255 time=2384.6 ms 64 bytes from (216.185.106.18): icmp_seq=69 ttl=255 time=1511.2 ms 64 bytes from (216.185.106.18): icmp_seq=70 ttl=255 time=666.1 ms 64 bytes from (216.185.106.18): icmp_seq=71 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=72 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=73 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=74 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=75 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=76 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=77 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=78 ttl=255 time=0.1 ms 64 bytes from (216.185.106.18): icmp_seq=79 ttl=255 time=0.1 ms The hardware in question are two Athlon servers with VIA KT133 chipset, 512Mb RAM, and IDE drives. One server uses the tulip network driver for a Netgear FA-310. The other uses the NatSim DP83810 network driver for the FA-312 and both exhibit the same problem. I've had 3com 3c900 series cards in the machines as well and the problem still persisted. One other interesting little fact is that if I ping the problem machines from a good machine I always get 0.1 ms response times, even while the pings from the problem machines are showing latency. I hope this is enough information for someone to work with. I'm at a loss for what the problem is and unfortunately I'm no kernel hacker. I appreciate any help you guys can offer. Thank you, Daniel Walton - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: 2.4.0 Networking oddity
The server in question is running the tulip driver. dmesg reports: Linux Tulip driver version 0.9.13 (January 2, 2001) I have seen this same behavior on a couple of my servers running 3com 3c905c adaptors as well. The last time I was experiencing it I rebooted the system and it didn't solve the problem. When it came up it was still lagging. This would lead me to believe that it is caused by some sort of network condition, but what I don't know. If anyone has ideas, I'd be more than happy to run tests/provide more info.. -Dan At 10:14 PM 1/28/2001 -0500, you wrote: >In mailing-lists.linux-kernel, you wrote: > > >I am running a web server under the new 2.4.0 kernel and am experiencing > >some intermittent odd behavior from the kernel. The machine will sometimes > >go through cycles where network response becomes slow even though top > >reports over 60% idle CPU time. When this is happening ping goes from > >reasonable response times to response times of several seconds in cycles of > >about 15 to 20 seconds. > >FWIW, I have seen behaviour like this under kernel 2.2.x and 2.4.x, >for me taking the interface down and then bringing it back up usually >makes the problem stop, at least for the moment. > >I have always assumed that it is caused by a bug in the Ethernet card >driver, as the first time I noticed this behaviour, I was using the >Realtek 8139 driver about two years ago, it was really not good >hardware and the driver was pretty new. Anyway, it would do this, so >I contacted Donald Becker about it, he pointed me to a newer version >of the driver that did it _much_ less often. > >Cheers, >Wayne - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
2.4.0 Networking oddity
I am running a web server under the new 2.4.0 kernel and am experiencing some intermittent odd behavior from the kernel. The machine will sometimes go through cycles where network response becomes slow even though top reports over 60% idle CPU time. When this is happening ping goes from reasonable response times to response times of several seconds in cycles of about 15 to 20 seconds. As a test I pinged another machine on the same network segment and received the same results listed above. On the other hand, I pinged from the other machine on the LAN to the problem machine and the ping times were a consistent 0.1ms. This tells me two things. One, that the network switch was not causing the problem, and two, that the problem is very likely somewhere in the handoff of packets from kernel-land to user-land on the problem server. Here is the ping results from the problem server to another machine on the same segment: 77 packets transmitted, 77 packets received, 0% packet loss round-trip min/avg/max = 0.2/4368.1/15126.6 ms Here are the ping results from the other machine to the problem server taken at exactly the same time: 116 packets transmitted, 115 packets received, 0% packet loss round-trip min/avg/max = 0.1/0.1/0.3 ms A little information about what I'm running. The server is running about 700Kbps continuous network output from nearly a thousand concurrent connections. The web server is a single process which utilizes the select/poll method of multiplexing. The machine is an 1gig Athlon processor with 512megs with RedHat 6.2 installed. I have the following tweaks setup in my rc.local file: echo "7168 32767 65535" > /proc/sys/net/ipv4/tcp_mem echo 32768 > /proc/sys/net/ipv4/tcp_max_orphans echo 4096 > /proc/sys/net/ipv4/tcp_max_syn_backlog echo 1 > /proc/sys/net/ipv4/tcp_syncookies echo 30 > /proc/sys/net/ipv4/tcp_fin_timeout echo 4 > /proc/sys/net/ipv4/tcp_syn_retries echo 7 > /proc/sys/net/ipv4/tcp_retries2 echo 300 > /proc/sys/net/ipv4/tcp_keepalive_time echo 30 > /proc/sys/net/ipv4/tcp_keepalive_intvl echo 16384 > /proc/sys/fs/file-max echo 16384 > /proc/sys/kernel/rtsig-max Am I simply missing something in my tweaks or is this a bug? I would be happy to supply more information if it would help anyone in the know on a problem like this. I appreciate any light anyone can shed on this subject. I've been trying to find the source of this problem for some time now. Daniel Walton - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: Out of socket memory? (2.4.0-test11)
I'm not quite clear how the settings under /proc/sys/vm/* would effect the problem. I neglected to mention in my previous post that all web content is served directly from the memory of the web server (no file accesses). The only file accesses that happen are from a MySQL server which gets queried about once a second. Here's the output of /proc/meminfo. I'm not sure how helpful it is. I was kinda hoping for something that would allow me to see how much memory had been allocated for sockets and what the max was. [root@s4 /proc]# cat meminfo total:used:free: shared: buffers: cached: Mem: 261742592 122847232 1388953600 1757184 88633344 Swap: 2713927680 271392768 MemTotal: 255608 kB MemFree:135640 kB MemShared: 0 kB Buffers: 1716 kB Cached: 86556 kB Active: 15684 kB Inact_dirty: 72588 kB Inact_clean: 0 kB Inact_target: 68 kB HighTotal: 0 kB HighFree:0 kB LowTotal: 255608 kB LowFree:135640 kB SwapTotal: 265032 kB SwapFree: 265032 kB -Dan At 12:30 AM 12/7/2000 -0500, you wrote: >backlog queue? tuning /proc/sys/vm/*? > > > problem? Is there any way I can get runtime information from the > kernel on > > things like amount of socket memory used and amount available? Am I using > >/proc/meminfo? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Out of socket memory? (2.4.0-test11)
Hello, I've been having a problem with a high volume Linux web server. This particular web server used to be a FreeBSD machine and I've been trying to successfully make the switch for some time now. I've been trying the 2.4 development kernels as they come out and I've been tweaking the /proc filesystem variables but so far nothing seems to have fixed the problem. The problem is that I get "Out of socket memory" errors and the networking locks up. Sometimes the server will go for weeks without running into the problem and other times it'll last 30 minutes. The hardware in question is an 1Ghz Athalon system with 256Mb of ram and an IDE hard disk. I've tried every 2.4 test kernel to date. The web server is a specialized web server running about 10 million hits a day. Of the 256Mb of ram the web server uses 40Mb and there are no other significant memory consuming processes on the system. Currently I am using the following /proc modifications in the rc.local file. echo "7168 11776 16384" > /proc/sys/net/ipv4/tcp_mem echo 32768 > /proc/sys/net/ipv4/tcp_max_orphans What am I doing wrong? Is this a kernel problem or a configuration problem? Is there any way I can get runtime information from the kernel on things like amount of socket memory used and amount available? Am I using the right variables to increase available socket memory and just not giving it enough yet? I appreciate any help provided. Thank you, Daniel Walton - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
