diff options
| author | Matthew Whitehead <tedheadster@gmail.com> | 2017-04-19 12:37:10 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-04-21 13:22:34 -0400 |
| commit | 7acf8a1e8a28b3d7407a8d8061a7d0766cfac2f4 (patch) | |
| tree | 34fb2d27d86e816f25b4a41f0d5d6b8d837f5bd9 /net | |
| parent | 20da848f8e5c2d911ee65dda1776d0f2a2408e01 (diff) | |
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 'net')
| -rw-r--r-- | net/core/dev.c | 4 | ||||
| -rw-r--r-- | net/core/sysctl_net_core.c | 8 |
2 files changed, 11 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 5d33e2baab2b..1c53c055b197 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3441,6 +3441,7 @@ EXPORT_SYMBOL(netdev_max_backlog); int netdev_tstamp_prequeue __read_mostly = 1; int netdev_budget __read_mostly = 300; +unsigned int __read_mostly netdev_budget_usecs = 2000; int weight_p __read_mostly = 64; /* old backlog weight */ int dev_weight_rx_bias __read_mostly = 1; /* bias for backlog weight */ int dev_weight_tx_bias __read_mostly = 1; /* bias for output_queue quota */ @@ -5307,7 +5308,8 @@ out_unlock: static __latent_entropy void net_rx_action(struct softirq_action *h) { struct softnet_data *sd = this_cpu_ptr(&softnet_data); - unsigned long time_limit = jiffies + 2; + unsigned long time_limit = jiffies + + usecs_to_jiffies(netdev_budget_usecs); int budget = netdev_budget; LIST_HEAD(list); LIST_HEAD(repoll); diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 7f9cc400eca0..ea23254b2457 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -452,6 +452,14 @@ static struct ctl_table net_core_table[] = { .extra1 = &one, .extra2 = &max_skb_frags, }, + { + .procname = "netdev_budget_usecs", + .data = &netdev_budget_usecs, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + }, { } }; |