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<== Date ==> <== Thread ==>

Subject: Linux network tuning
From: Eric Norum <wenorum@lbl.gov>
To: EPICS Tech-Talk <tech-talk@aps.anl.gov>
Date: Wed, 5 Sep 2018 11:06:38 -0700
Are there guidelines for tuning the network parameters for a Linux host running a bunch of EPICS soft IOCs?  We were seeing some issues with CA clients seeing delays of over a second for ‘get' requests.  Setting the values shown here:
net.core.netdev_max_backlog = 5000
net.core.rmem_max = 8388608
net.core.wmem_max = 8388608
net.core.rmem_default = 124928
net.core.wmem_default = 124928
net.ipv4.tcp_rmem = 4096 87380 8388608
net.ipv4.tcp_wmem = 4096 65536 8388608
net.ipv4.tcp_mem = 8388608 8388608 8388608
seems to have improved things.  But I don’t know if those numbers, which I got from a google search, are way too big, or not yet big enough or completely weird.
Suggestions welcomed.

Machine details:
  • 8 cores
  • 24 GiB RAM
  • 1 TB SSD
  • Gigabit Ethernet
  • EPICS R3.15.4
Load average in the 3 to 4 range but CPU utilization as shown by ‘top’ showed at least 60% idle even when clients were experiencing the slow response.

 -- 
Eric Norum
wenorum@lbl.gov




Replies:
Re: Linux network tuning Kyle Lanclos
Re: Linux network tuning Fors, Thomas L.

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