Re: [lwip-devel] LwIP SMP Experience

[Joel Cunningham]

> On Mar 24, 2017, at 9:33 AM, Simon Goldschmidt <address@hidden> wrote:
> 
> Joel Cunningham wrote:
>> I have a couple products that run LwIP in an SMP environment with 
>> CORE_LOCKING enabled. I haven’t done any SMP optimizations yet,
> 
> The performance problem I saw was not really only SMP related but could 
> prefer high priority connections over low priority (at least for TX, RX is a 
> bit trickier).
> You (like the Minix and Hurd services) solved this by having multiple threads 
> at socket level but not at pcb level…
> 
>> [..] we ran into issue with this because the event_callback in sockets.c 
>> calls sys_sem_signal() while the spinlock was held
> 
> I'd rather fix this by saying we must not call sys_sem_signal() or 
> sys_mbox_post() calls from SYS_ARCH_PROTECTed regions.
> That could possibly be done by protecting the select_sb_list using an 
> additional (global) mutex instead of SYS_ARCH_PROTECT.
> 

Agreed that’s another approach.  I’m fine with that, especially if it was never 
intended to perform any sleeping/task switch while inside SYS_ARCH_PROTECT.  
I’ll open a task

Joel