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PATCH出来了. 是针对2.6.13-15-smp的.
将代码存到文件seeker中, 放在linux source根下, 然后patch -p1 < seeker
然后编译KERNEL.启动.
我初步测试网络下载的速度
在双CPU机器上, 在IPTABLES 的INPUT链安上2400行IP和PORT匹配(目的是故意模拟
高负载的情况). 有PATCH, 网络下载速度比没有可以高出一倍. 因为利用的双CPU.
这个有可能是最好的解决方案. 如果4个CPU,可能将负载能力提高4倍(至少2倍).
IRQBALANCE不需要了.
NAT情况我限于条件,测试的十分不完全.
欢迎测试.
以后我还会给出module, 不用编译KERNEL就可以测试了.
- --- old/net/ipv4/ip_input.c 2007-09-20 20:50:31.000000000 +0800
- +++ new/net/ipv4/ip_input.c 2007-09-21 05:52:40.000000000 +0800
- @@ -362,6 +362,198 @@
- return NET_RX_DROP;
- }
-
- +
- +#define CONFIG_BOTTOM_SOFTIRQ_SMP
- +#define CONFIG_BOTTOM_SOFTIRQ_SMP_SYSCTL
- +
- +#ifdef CONFIG_BOTTOM_SOFTIRQ_SMP
- +
- +/*
- + *
- +Bottom Softirq Implementation. John Ye, 2007.08.27
- +
- +Why this patch:
- +Make kernel be able to concurrently execute softirq's net code on SMP system.
- +Takes full advantages of SMP to handle more packets and greatly raises NIC throughput.
- +The current kernel's net packet processing logic is:
- +1) The CPU which handles a hardirq must be executing its related softirq.
- +2) One softirq instance(irqs handled by 1 CPU) can't be executed on more than 2 CPUs
- +at the same time.
- +The limitation make kernel network be hard to take the advantages of SMP.
- +
- +How this patch:
- +It splits the current softirq code into 2 parts: the cpu-sensitive top half,
- +and the cpu-insensitive bottom half, then make bottom half(calld BS) be
- +executed on SMP concurrently.
- +The two parts are not equal in terms of size and load. Top part has constant code
- +size(mainly, in net/core/dev.c and NIC drivers), while bottom part involves
- +netfilter(iptables) whose load varies very much. An iptalbes with 1000 rules to match
- +will make the bottom part's load be very high. So, if the bottom part softirq
- +can be randomly distributed to processors and run concurrently on them, the network will
- +gain much more packet handling capacity, network throughput will be be increased
- +remarkably.
- +
- +Where useful:
- +It's useful on SMP machines that meet the following 2 conditions:
- +1) have high kernel network load, for example, running iptables with thousands of rules, etc).
- +2) have more CPUs than active NICs, e.g. a 4 CPUs machine with 2 NICs).
- +On these system, with the increase of softirq load, some CPUs will be idle
- +while others(number is equal to # of NIC) keeps busy.
- +IRQBALANCE will help, but it only shifts IRQ among CPUS, makes no softirq concurrency.
- +Balancing the load of each cpus will not remarkably increase network speed.
- +
- +Where NOT useful:
- +If the bottom half of softirq is too small(without running iptables), or the network
- +is too idle, BS patch will not be seen to have visible effect. But It has no
- +negative affect either.
- +User can turn on/off BS functionality by /proc/sys/net/bs_enable switch.
- +
- +How to test:
- +On a linux box, run iptables, add 2000 rules to table filter & table nat to simulate huge
- +softirq load. Then, open 20 ftp sessions to download big file. On another machine(who
- +use this test machine as gateway), open 20 more ftp download sessions. Compare the speed,
- +without BS enabled, and with BS enabled.
- +cat /proc/sys/net/bs_enable. this is a switch to turn on/off BS
- +cat /proc/sys/net/bs_status. this shows the usage of each CPUs
- +Test shown that when bottom softirq load is high, the network throughput can be nearly
- +doubled on 2 CPUs machine. hopefully it may be quadrupled on a 4 cpus linux box.
- +
- +Bugs:
- +It will NOT allow hotpug CPU.
- +It only allows incremental CPUs ids, starting from 0 to num_online_cpus().
- +for example, 0,1,2,3 is OK. 0,1,8,9 is KO.
- +
- +Some considerations in the future:
- +1) With BS patch, the irq balance code on arch/i386/kernel/io_apic.c seems no need any more,
- +at least not for network irq.
- +2) Softirq load will become very small. It only run the top half of old softirq, which
- +is much less expensive than bottom half---the netfilter program.
- +To let top softirq process more packets, cant these 3 network parameters be enlarged?
- +extern int netdev_max_backlog = 1000;
- +extern int netdev_budget = 300;
- +extern int weight_p = 64;
- +3) Now, BS are running on built-in keventd thread, we can create new workqueues to let it run on?
- +
- +Signed-off-by: John Ye (Seeker) <[email]johny@webizmail.com[/email]>
- + *
- + */
- +
- +#define BS_USE_PERCPU_DATA
- +
- +struct cpu_stat {
- + unsigned long irqs; //total irqs
- + unsigned long dids; //I did,
- + unsigned long others;
- + unsigned long works;
- +};
- +#define BS_CPU_STAT_DEFINED
- +
- +static int nr_cpus = 0;
- +
- +#ifdef BS_USE_PERCPU_DATA
- +static DEFINE_PER_CPU(struct sk_buff_head, bs_cpu_queues); // cacheline_aligned_in_smp;
- +static DEFINE_PER_CPU(struct work_struct, bs_works);
- +struct cpu_stat bs_cpu_status[NR_CPUS];
- +#else
- +#define NR_CPUS 8
- +static struct sk_buff_head bs_cpu_queues[NR_CPUS];
- +static struct work_struct bs_works[NR_CPUS];
- +static struct cpu_stat bs_cpu_status[NR_CPUS];
- +#endif
- +
- +int bs_enable = 1;
- +
- +static int ip_rcv1(struct sk_buff *skb, struct net_device *dev)
- +{
- + return NF_HOOK_COND(PF_INET, NF_IP_PRE_ROUTING, skb, dev, NULL, ip_rcv_finish, nf_hook_input_cond(skb));
- +}
- +
- +
- +static void bs_func(void *data)
- +{
- + int flags, num, cpu;
- + struct sk_buff *skb, *last;
- + struct work_struct *bs_works;
- + struct sk_buff_head *q;
- + cpu = smp_processor_id();
- +
- +
- +#ifdef BS_USE_PERCPU_DATA
- + bs_works = &per_cpu(bs_works, cpu);
- + q = &per_cpu(bs_cpu_queues, cpu);
- +#else
- + bs_works = &bs_works[cpu];
- + q = &bs_cpu_queues[cpu];
- +#endif
- +
- + local_bh_disable();
- +restart:
- + num = 0;
- + while(1) {
- + last = skb;
- + spin_lock_irqsave(&q->lock, flags);
- + skb = __skb_dequeue(q);
- + spin_unlock_irqrestore(&q->lock, flags);
- + if(!skb) break;
- + num++;
- + //local_bh_disable();
- + ip_rcv1(skb, skb->dev);
- + //__local_bh_enable(); //sub_preempt_count(SOFTIRQ_OFFSET - 1);
- + }
- +
- + bs_cpu_status[cpu].others += num;
- + if(num > 0) { goto restart; }
- +
- + __local_bh_enable(); //sub_preempt_count(SOFTIRQ_OFFSET - 1);
- + bs_works->func = 0;
- +
- + return;
- +}
- +
- +/* COPY_IN_START_FROM kernel/workqueue.c */
- +struct cpu_workqueue_struct {
- +
- + spinlock_t lock;
- +
- + long remove_sequence; /* Least-recently added (next to run) */
- + long insert_sequence; /* Next to add */
- +
- + struct list_head worklist;
- + wait_queue_head_t more_work;
- + wait_queue_head_t work_done;
- +
- + struct workqueue_struct *wq;
- + task_t *thread;
- +
- + int run_depth; /* Detect run_workqueue() recursion depth */
- +} ____cacheline_aligned;
- +
- +
- +struct workqueue_struct {
- + struct cpu_workqueue_struct cpu_wq[NR_CPUS];
- + const char *name;
- + struct list_head list; /* Empty if single thread */
- +};
- +/* COPY_IN_END_FROM kernel/worqueue.c */
- +
- +extern struct workqueue_struct *keventd_wq;
- +
- +/* Preempt must be disabled. */
- +static void __queue_work(struct cpu_workqueue_struct *cwq,
- + struct work_struct *work)
- +{
- + unsigned long flags;
- +
- + spin_lock_irqsave(&cwq->lock, flags);
- + work->wq_data = cwq;
- + list_add_tail(&work->entry, &cwq->worklist);
- + cwq->insert_sequence++;
- + wake_up(&cwq->more_work);
- + spin_unlock_irqrestore(&cwq->lock, flags);
- +}
- +#endif //CONFIG_BOTTOM_SOFTIRQ_SMP
- +
- +
- /*
- * Main IP Receive routine.
- */
- @@ -424,8 +616,73 @@
- }
- }
-
- +#ifdef CONFIG_BOTTOM_SOFTIRQ_SMP
- + if(!nr_cpus)
- + nr_cpus = num_online_cpus();
- +
- + if(bs_enable && nr_cpus > 1 && iph->protocol != IPPROTO_ICMP) {
- + //if(bs_enable && iph->protocol == IPPROTO_ICMP) { //test on icmp first
- + unsigned int flags, cur, cpu;
- + struct work_struct *bs_works;
- + struct sk_buff_head *q;
- +
- + cur = smp_processor_id();
- +
- + bs_cpu_status[cur].irqs++;
- +
- + //random distribute
- + cpu = (bs_cpu_status[cur].irqs % nr_cpus);
- + if(cpu == cur) {
- + bs_cpu_status[cpu].dids++;
- + return ip_rcv1(skb, dev);
- + }
- +
- +#ifdef BS_USE_PERCPU_DATA
- + q = &per_cpu(bs_cpu_queues, cpu);
- +#else
- + q = &bs_cpu_queues[cpu];
- +#endif
- +
- + if(!q->next) { // || skb_queue_len(q) == 0 ) {
- + skb_queue_head_init(q);
- + }
- +
- +
- +#ifdef BS_USE_PERCPU_DATA
- + bs_works = &per_cpu(bs_works, cpu);
- +#else
- + bs_works = &bs_works[cpu];
- +#endif
- + /*
- + local_irq_save(flags);
- + SKB_CB(skb)->dev = dev;
- + SKB_CB(skb)->ptype = pt;
- + */
- + spin_lock_irqsave(&q->lock, flags);
- + __skb_queue_tail(q, skb);
- + spin_unlock_irqrestore(&q->lock, flags);
- + //if(net_ratelimit()) printk("qlen %d\n", q->qlen);
- +
- + //local_irq_restore(flags);
- + if (!bs_works->func) {
- + INIT_WORK(bs_works, bs_func, q);
- + bs_cpu_status[cpu].works++;
- + preempt_disable();
- + __queue_work(keventd_wq->cpu_wq + cpu, bs_works);
- + preempt_enable();
- + }
- + } else {
- + int cpu = smp_processor_id();
- + bs_cpu_status[cpu].irqs++;
- + bs_cpu_status[cpu].dids++;
- + return ip_rcv1(skb, dev);
- + }
- + return 0;
- +#else
- return NF_HOOK_COND(PF_INET, NF_IP_PRE_ROUTING, skb, dev, NULL,
- - ip_rcv_finish, nf_hook_input_cond(skb));
- + ip_rcv_finish, nf_hook_input_cond(skb));
- +#endif //CONFIG_BOTTOM_SOFTIRQ_SMP
- +
-
- inhdr_error:
- IP_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
- --- old/net/sysctl_net.c 2007-09-20 23:30:29.000000000 +0800
- +++ new/net/sysctl_net.c 2007-09-20 23:28:06.000000000 +0800
- @@ -30,6 +30,22 @@
- extern struct ctl_table tr_table[];
- #endif
-
- +
- +#define CONFIG_BOTTOM_SOFTIRQ_SMP_SYSCTL
- +#ifdef CONFIG_BOTTOM_SOFTIRQ_SMP_SYSCTL
- +#if !defined(BS_CPU_STAT_DEFINED)
- +struct cpu_stat {
- + unsigned long irqs; //total irqs
- + unsigned long dids; //I did,
- + unsigned long others;
- + unsigned long works;
- +};
- +#endif
- +extern struct cpu_stat bs_cpu_status[NR_CPUS];
- +
- +extern int bs_enable;
- +#endif
- +
- struct ctl_table net_table[] = {
- {
- .ctl_name = NET_CORE,
- @@ -61,5 +77,26 @@
- .child = tr_table,
- },
- #endif
- +
- +#ifdef CONFIG_BOTTOM_SOFTIRQ_SMP_SYSCTL
- + {
- + .ctl_name = 99,
- + .procname = "bs_status",
- + .data = &bs_cpu_status,
- + .maxlen = sizeof(bs_cpu_status),
- + .mode = 0644,
- + .proc_handler = &proc_dointvec,
- + },
- +
- + {
- + .ctl_name = 99,
- + .procname = "bs_enable",
- + .data = &bs_enable,
- + .maxlen = sizeof(int),
- + .mode = 0644,
- + .proc_handler = &proc_dointvec,
- + },
- +#endif
- +
- { 0 },
- };
- --- old/kernel/workqueue.c 2007-09-21 04:48:13.000000000 +0800
- +++ new/kernel/workqueue.c 2007-09-21 04:47:49.000000000 +0800
- @@ -384,7 +384,11 @@
- kfree(wq);
- }
-
- +/*
- static struct workqueue_struct *keventd_wq;
- +*/
- +struct workqueue_struct *keventd_wq;
- +EXPORT_SYMBOL(keventd_wq);
-
- int fastcall schedule_work(struct work_struct *work)
- {
[ 本帖最后由 思一克 于 2007-9-20 22:17 编辑 ] |
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楼主: 思一克
发表于 2007-07-17 14:21
