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| author | Matthew Whitehead <tedheadster@gmail.com> | 2017-04-19 18:37:10 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-04-21 19:22:34 +0200 |
| commit | 7acf8a1e8a28b3d7407a8d8061a7d0766cfac2f4 (patch) | |
| tree | 34fb2d27d86e816f25b4a41f0d5d6b8d837f5bd9 /Documentation/sysctl | |
| parent | Merge branch 'iptunnel-policy-based-routing' (diff) | |
| download | linux-7acf8a1e8a28b3d7407a8d8061a7d0766cfac2f4.tar.xz linux-7acf8a1e8a28b3d7407a8d8061a7d0766cfac2f4.zip | |
Replace 2 jiffies with sysctl netdev_budget_usecs to enable softirq tuning
Constants used for tuning are generally a bad idea, especially as hardware
changes over time. Replace the constant 2 jiffies with sysctl variable
netdev_budget_usecs to enable sysadmins to tune the softirq processing.
Also document the variable.
For example, a very fast machine might tune this to 1000 microseconds,
while my regression testing 486DX-25 needs it to be 4000 microseconds on
a nearly idle network to prevent time_squeeze from being incremented.
Version 2: changed jiffies to microseconds for predictable units.
Signed-off-by: Matthew Whitehead <tedheadster@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/sysctl')
| -rw-r--r-- | Documentation/sysctl/net.txt | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/Documentation/sysctl/net.txt b/Documentation/sysctl/net.txt index 2ebabc93014a..14db18c970b1 100644 --- a/Documentation/sysctl/net.txt +++ b/Documentation/sysctl/net.txt @@ -188,7 +188,16 @@ netdev_budget Maximum number of packets taken from all interfaces in one polling cycle (NAPI poll). In one polling cycle interfaces which are registered to polling are -probed in a round-robin manner. +probed in a round-robin manner. Also, a polling cycle may not exceed +netdev_budget_usecs microseconds, even if netdev_budget has not been +exhausted. + +netdev_budget_usecs +--------------------- + +Maximum number of microseconds in one NAPI polling cycle. Polling +will exit when either netdev_budget_usecs have elapsed during the +poll cycle or the number of packets processed reaches netdev_budget. netdev_max_backlog ------------------ |