Messages in this thread | | | Date | Sun, 29 Jun 2003 10:37:12 -0400 (EDT) | From | Ronghua Zhang <> | Subject | How to send multiple TCP packets from a kernel thread ASAP? |
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Hi, I came to a situation that requires to send multiple TCP packets (one for each connection) from a kernel thread as soon as possible. The following is the skeleton of my code:
kernel_thread() { foreach sk in (alive connections){ tp = &(sk->tp_pinfo.af_tcp);
skb = alloc_skb(xxx, GFP_ATOMIC); /* build TCP header */ tcp_build_and_update_options(.....); tp->af_specific->send_check(sk, th, skb->len, skb);
tp->af_specific->queue_xmit(skb); printk("packet send out for sk %p, at %lu\n", sk, jiffies); } }
the output is always like this: packet send out for sk 1 at 1000 packet send out for sk 2 at 1001 packet send out for sk 3 at 1002 ...
It looks like this kernel thread get rescheduled after it has sent out 1 packet. But why? each iteration certainly does not need 10ms, why it get rescheduled? Is it because af_specific->queue_xmit() is blocking operation? but I notice that tcp_transmit_skb() also call it, and tcp_transmit_skb() should not call any blockalbe operation. I try to increase its priority or change its schedule policy,but has no effect at all. Any suggestion is appreciated! This is really urgent.
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