Q: What's the best way to discover the cause of network timeouts?
Background: Under regular load my network connection appears to work fine. However, after ~15mins of heavy load I get network timeouts, disconnections, and can't even ping local addresses. After about 4-5 minutes of complete inactivity, things will start up again, but only for a further minute or so. This pattern repeats (1 min of connection, 4-5 mins of timeouts) until I reboot (ifconfig down/up doesn't clear things up). During this time, only this machines connection seems to be affected - I can connect to the outside and maintain a good connection from other machines (so long as I bypass this machine).
How I'm stressing the connection: 32 simultaneous SSL connections to my nntp provider. Maxing out at ~1.0MB/s total. No ISP or news provider caps, and my machine / net interface should comfortably sustain this without issue (as it has on other operating systems). I've attempted the same load with two different nntp apps. Same result. Top shows my machine, memory and swap are all fine before and during these periods. Router shows no dropped packets or network errors.
Things I've tried:
pf enabled / disabled - no effect.
dnsmasq enabled / disabled - no effect.
different apps - no effect.
sysclt tuning - no effect.
I tried tuning network sysctl options as described in the handbook, 'man tuning' and some of the more sensible online howtos. Same behavior.
I've been trying to get to the bottom of this for a few days, and am now out of ideas. I'm currently having to reboot my machine every 30 mins or so to clear these connections.
It feels like I'm filling buffers faster than I'm clearing them, or exceeding some hard limit, but that isn't supported by the sysctl tuning I've attempted. It seems I might need to learn some lower level tools to determine the cause.
7.0-RELEASE-p7, all packages fully up-to-date.
Ideas anyone?
Background: Under regular load my network connection appears to work fine. However, after ~15mins of heavy load I get network timeouts, disconnections, and can't even ping local addresses. After about 4-5 minutes of complete inactivity, things will start up again, but only for a further minute or so. This pattern repeats (1 min of connection, 4-5 mins of timeouts) until I reboot (ifconfig down/up doesn't clear things up). During this time, only this machines connection seems to be affected - I can connect to the outside and maintain a good connection from other machines (so long as I bypass this machine).
How I'm stressing the connection: 32 simultaneous SSL connections to my nntp provider. Maxing out at ~1.0MB/s total. No ISP or news provider caps, and my machine / net interface should comfortably sustain this without issue (as it has on other operating systems). I've attempted the same load with two different nntp apps. Same result. Top shows my machine, memory and swap are all fine before and during these periods. Router shows no dropped packets or network errors.
Things I've tried:
pf enabled / disabled - no effect.
dnsmasq enabled / disabled - no effect.
different apps - no effect.
sysclt tuning - no effect.
I tried tuning network sysctl options as described in the handbook, 'man tuning' and some of the more sensible online howtos. Same behavior.
I've been trying to get to the bottom of this for a few days, and am now out of ideas. I'm currently having to reboot my machine every 30 mins or so to clear these connections.
It feels like I'm filling buffers faster than I'm clearing them, or exceeding some hard limit, but that isn't supported by the sysctl tuning I've attempted. It seems I might need to learn some lower level tools to determine the cause.
7.0-RELEASE-p7, all packages fully up-to-date.
Ideas anyone?
