On 12/14/2016 01:57 PM, Pavel Machek wrote:
> Hi!
>
>> So if there is a long time before handling interrupts,
>> I guess that it makes sense that one stream could
>> get an advantage in the net scheduler.
>>
>> If I find the time, and if no one beats me to it, I will try to replace
>> the normal timers with HR timers + a smaller default timeout.
>>
> Can you try something like this? Highres timers will be needed, too,
> but this fixes the logic problem.
Hello Pavel
I tried your patch, but unfortunately I get a tx queue timeout.
After that, I cannot ping.
[ 22.075782] ------------[ cut here ]------------
[ 22.080430] WARNING: CPU: 0 PID: 0 at net/sched/sch_generic.c:316
dev_watchdog+0x240/0x258
[ 22.088704] NETDEV WATCHDOG: eth0 (stmmaceth): transmit queue 0 timed out
[ 22.095491] Modules linked in:
[ 22.098552] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.0-axis3-devel #126
[ 22.105592] Hardware name: Axis ARTPEC-6 Platform
[ 22.110301] [<80110568>] (unwind_backtrace) from [<8010c2bc>]
(show_stack+0x18/0x1c)
[ 22.118043] [<8010c2bc>] (show_stack) from [<80433544>]
(dump_stack+0x80/0xa0)
[ 22.125264] [<80433544>] (dump_stack) from [<8011f9f0>] (__warn+0xe0/0x10c)
[ 22.132221] [<8011f9f0>] (__warn) from [<8011fadc>]
(warn_slowpath_fmt+0x40/0x50)
[ 22.139700] [<8011fadc>] (warn_slowpath_fmt) from [<805e626c>]
(dev_watchdog+0x240/0x258)
[ 22.147875] [<805e626c>] (dev_watchdog) from [<801826c8>]
(call_timer_fn+0x44/0x208)
[ 22.155613] [<801826c8>] (call_timer_fn) from [<80182934>]
(expire_timers+0xa8/0x15c)
[ 22.163437] [<80182934>] (expire_timers) from [<80182a74>]
(run_timer_softirq+0x8c/0x164)
[ 22.171610] [<80182a74>] (run_timer_softirq) from [<80124a7c>]
(__do_softirq+0xac/0x3f0)
[ 22.179696] [<80124a7c>] (__do_softirq) from [<80125124>]
(irq_exit+0xf0/0x158)
[ 22.187003] [<80125124>] (irq_exit) from [<8016ffd4>]
(__handle_domain_irq+0x60/0xb8)
[ 22.194828] [<8016ffd4>] (__handle_domain_irq) from [<801014c4>]
(gic_handle_irq+0x4c/0x9c)
[ 22.203175] [<801014c4>] (gic_handle_irq) from [<806cc48c>]
(__irq_svc+0x6c/0xa8)
[ 22.210648] Exception stack(0x80b01f60 to 0x80b01fa8)
[ 22.215694] 1f60: 00000000 bf5c03f0 80b01fb8 8011a060 00000000 00000001
80b03c9c 80b03c2c
[ 22.223865] 1f80: 80b1c045 80b1c045 00000001 00000000 80a673f0 80b01fb0
801090c0 801090c4
[ 22.232032] 1fa0: 60000013 ffffffff
[ 22.235520] [<806cc48c>] (__irq_svc) from [<801090c4>]
(arch_cpu_idle+0x38/0x44)
[ 22.242914] [<801090c4>] (arch_cpu_idle) from [<80160f00>]
(cpu_startup_entry+0xd8/0x148)
[ 22.251089] [<80160f00>] (cpu_startup_entry) from [<80a00c44>]
(start_kernel+0x360/0x3c8)
[ 22.259269] ---[ end trace e04d3944bdde616a ]---
I patched both stmmac_tso_xmit and stmmac_xmit, as instructed.
Here is the diff:
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2090,8 +2090,9 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb,
struct net_device *dev)
/* Manage tx mitigation */
priv->tx_count_frames += nfrags + 1;
if (likely(priv->tx_coal_frames > priv->tx_count_frames)) {
- mod_timer(&priv->txtimer,
- STMMAC_COAL_TIMER(priv->tx_coal_timer));
+ if (priv->tx_count_frames == nfrags + 1)
+ mod_timer(&priv->txtimer,
+ STMMAC_COAL_TIMER(priv->tx_coal_timer));
} else {
priv->tx_count_frames = 0;
priv->hw->desc->set_tx_ic(desc);
@@ -2292,8 +2293,9 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb,
struct net_device *dev)
*/
priv->tx_count_frames += nfrags + 1;
if (likely(priv->tx_coal_frames > priv->tx_count_frames)) {
- mod_timer(&priv->txtimer,
- STMMAC_COAL_TIMER(priv->tx_coal_timer));
+ if (priv->tx_count_frames == nfrags + 1)
+ mod_timer(&priv->txtimer,
+ STMMAC_COAL_TIMER(priv->tx_coal_timer));
} else {
priv->tx_count_frames = 0;
priv->hw->desc->set_tx_ic(desc);
Without your patch, I get no tx queue timeout, and ping works fine.
>
> You'll need to apply it twice as code is copy&pasted.
>
> Best regards,
> Pavel
>
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>
> */
> priv->tx_count_frames += nfrags + 1;
> if (likely(priv->tx_coal_frames > priv->tx_count_frames)) {
> - mod_timer(&priv->txtimer,
> - STMMAC_COAL_TIMER(priv->tx_coal_timer));
> + if (priv->tx_count_frames == nfrags + 1)
> + mod_timer(&priv->txtimer,
> + STMMAC_COAL_TIMER(priv->tx_coal_timer));
> } else {
> priv->tx_count_frames = 0;
> priv->hw->desc->set_tx_ic(desc);
>
>
