Merge branch 'pktgen'
Jesper Dangaard Brouer says:
====================
Optimizing pktgen for single CPU performance
This series focus on optimizing "pktgen" for single CPU performance.
V2-series:
- Removed some patches
- Doc real reason for TX ring buffer filling up
NIC tuning for pktgen:
http://netoptimizer.blogspot.dk/2014/06/pktgen-for-network-overload-testing.html
General overload setup according to:
http://netoptimizer.blogspot.dk/2014/04/basic-tuning-for-network-overload.html
Hardware:
System: CPU E5-2630
NIC: Intel ixgbe/82599 chip
Testing done with net-next git tree on top of
commit 6623b41944 ("Merge branch 'master' of...jkirsher/net-next")
Pktgen script exercising race condition:
https://github.com/netoptimizer/network-testing/blob/master/pktgen/unit_test01_race_add_rem_device_loop.sh
Tool for measuring LOCK overhead:
https://github.com/netoptimizer/network-testing/blob/master/src/overhead_cmpxchg.c
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller
commit
edd79ca8b3
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@ -24,6 +24,34 @@ For monitoring and control pktgen creates:
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/proc/net/pktgen/ethX
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Tuning NIC for max performance
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==============================
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The default NIC setting are (likely) not tuned for pktgen's artificial
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overload type of benchmarking, as this could hurt the normal use-case.
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Specifically increasing the TX ring buffer in the NIC:
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# ethtool -G ethX tx 1024
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A larger TX ring can improve pktgen's performance, while it can hurt
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in the general case, 1) because the TX ring buffer might get larger
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than the CPUs L1/L2 cache, 2) because it allow more queueing in the
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NIC HW layer (which is bad for bufferbloat).
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One should be careful to conclude, that packets/descriptors in the HW
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TX ring cause delay. Drivers usually delay cleaning up the
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ring-buffers (for various performance reasons), thus packets stalling
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the TX ring, might just be waiting for cleanup.
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This cleanup issues is specifically the case, for the driver ixgbe
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(Intel 82599 chip). This driver (ixgbe) combine TX+RX ring cleanups,
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and the cleanup interval is affected by the ethtool --coalesce setting
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of parameter "rx-usecs".
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For ixgbe use e.g "30" resulting in approx 33K interrupts/sec (1/30*10^6):
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# ethtool -C ethX rx-usecs 30
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Viewing threads
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===============
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/proc/net/pktgen/kpktgend_0
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@ -69,8 +69,9 @@
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* for running devices in the if_list and sends packets until count is 0 it
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* also the thread checks the thread->control which is used for inter-process
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* communication. controlling process "posts" operations to the threads this
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* way. The if_lock should be possible to remove when add/rem_device is merged
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* into this too.
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* way.
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* The if_list is RCU protected, and the if_lock remains to protect updating
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* of if_list, from "add_device" as it invoked from userspace (via proc write).
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*
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* By design there should only be *one* "controlling" process. In practice
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* multiple write accesses gives unpredictable result. Understood by "write"
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@ -208,7 +209,7 @@
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#define T_REMDEVALL (1<<2) /* Remove all devs */
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#define T_REMDEV (1<<3) /* Remove one dev */
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/* If lock -- can be removed after some work */
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/* If lock -- protects updating of if_list */
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#define if_lock(t) spin_lock(&(t->if_lock));
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#define if_unlock(t) spin_unlock(&(t->if_lock));
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@ -241,6 +242,7 @@ struct pktgen_dev {
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struct proc_dir_entry *entry; /* proc file */
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struct pktgen_thread *pg_thread;/* the owner */
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struct list_head list; /* chaining in the thread's run-queue */
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struct rcu_head rcu; /* freed by RCU */
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int running; /* if false, the test will stop */
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@ -1737,14 +1739,14 @@ static int pktgen_thread_show(struct seq_file *seq, void *v)
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seq_puts(seq, "Running: ");
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if_lock(t);
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list_for_each_entry(pkt_dev, &t->if_list, list)
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rcu_read_lock();
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list_for_each_entry_rcu(pkt_dev, &t->if_list, list)
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if (pkt_dev->running)
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seq_printf(seq, "%s ", pkt_dev->odevname);
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seq_puts(seq, "\nStopped: ");
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list_for_each_entry(pkt_dev, &t->if_list, list)
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list_for_each_entry_rcu(pkt_dev, &t->if_list, list)
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if (!pkt_dev->running)
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seq_printf(seq, "%s ", pkt_dev->odevname);
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@ -1753,7 +1755,7 @@ static int pktgen_thread_show(struct seq_file *seq, void *v)
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else
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seq_puts(seq, "\nResult: NA\n");
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if_unlock(t);
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rcu_read_unlock();
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return 0;
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}
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@ -1878,10 +1880,8 @@ static struct pktgen_dev *__pktgen_NN_threads(const struct pktgen_net *pn,
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pkt_dev = pktgen_find_dev(t, ifname, exact);
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if (pkt_dev) {
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if (remove) {
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if_lock(t);
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pkt_dev->removal_mark = 1;
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t->control |= T_REMDEV;
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if_unlock(t);
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}
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break;
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}
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@ -1931,7 +1931,8 @@ static void pktgen_change_name(const struct pktgen_net *pn, struct net_device *d
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list_for_each_entry(t, &pn->pktgen_threads, th_list) {
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struct pktgen_dev *pkt_dev;
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list_for_each_entry(pkt_dev, &t->if_list, list) {
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rcu_read_lock();
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list_for_each_entry_rcu(pkt_dev, &t->if_list, list) {
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if (pkt_dev->odev != dev)
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continue;
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@ -1946,6 +1947,7 @@ static void pktgen_change_name(const struct pktgen_net *pn, struct net_device *d
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dev->name);
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break;
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}
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rcu_read_unlock();
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}
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}
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@ -2997,8 +2999,8 @@ static void pktgen_run(struct pktgen_thread *t)
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func_enter();
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if_lock(t);
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list_for_each_entry(pkt_dev, &t->if_list, list) {
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rcu_read_lock();
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list_for_each_entry_rcu(pkt_dev, &t->if_list, list) {
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/*
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* setup odev and create initial packet.
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@ -3007,18 +3009,18 @@ static void pktgen_run(struct pktgen_thread *t)
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if (pkt_dev->odev) {
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pktgen_clear_counters(pkt_dev);
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pkt_dev->running = 1; /* Cranke yeself! */
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pkt_dev->skb = NULL;
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pkt_dev->started_at = pkt_dev->next_tx = ktime_get();
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set_pkt_overhead(pkt_dev);
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strcpy(pkt_dev->result, "Starting");
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pkt_dev->running = 1; /* Cranke yeself! */
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started++;
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} else
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strcpy(pkt_dev->result, "Error starting");
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}
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if_unlock(t);
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rcu_read_unlock();
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if (started)
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t->control &= ~(T_STOP);
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}
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@ -3041,27 +3043,25 @@ static int thread_is_running(const struct pktgen_thread *t)
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{
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const struct pktgen_dev *pkt_dev;
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list_for_each_entry(pkt_dev, &t->if_list, list)
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if (pkt_dev->running)
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rcu_read_lock();
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list_for_each_entry_rcu(pkt_dev, &t->if_list, list)
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if (pkt_dev->running) {
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rcu_read_unlock();
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return 1;
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}
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rcu_read_unlock();
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return 0;
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}
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static int pktgen_wait_thread_run(struct pktgen_thread *t)
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{
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if_lock(t);
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while (thread_is_running(t)) {
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if_unlock(t);
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msleep_interruptible(100);
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if (signal_pending(current))
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goto signal;
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if_lock(t);
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}
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if_unlock(t);
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return 1;
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signal:
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return 0;
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@ -3166,10 +3166,10 @@ static int pktgen_stop_device(struct pktgen_dev *pkt_dev)
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return -EINVAL;
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}
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pkt_dev->running = 0;
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kfree_skb(pkt_dev->skb);
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pkt_dev->skb = NULL;
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pkt_dev->stopped_at = ktime_get();
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pkt_dev->running = 0;
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show_results(pkt_dev, nr_frags);
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@ -3180,9 +3180,8 @@ static struct pktgen_dev *next_to_run(struct pktgen_thread *t)
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{
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struct pktgen_dev *pkt_dev, *best = NULL;
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if_lock(t);
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list_for_each_entry(pkt_dev, &t->if_list, list) {
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rcu_read_lock();
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list_for_each_entry_rcu(pkt_dev, &t->if_list, list) {
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if (!pkt_dev->running)
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continue;
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if (best == NULL)
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@ -3190,7 +3189,8 @@ static struct pktgen_dev *next_to_run(struct pktgen_thread *t)
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else if (ktime_compare(pkt_dev->next_tx, best->next_tx) < 0)
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best = pkt_dev;
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}
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if_unlock(t);
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rcu_read_unlock();
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return best;
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}
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@ -3200,13 +3200,13 @@ static void pktgen_stop(struct pktgen_thread *t)
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func_enter();
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if_lock(t);
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rcu_read_lock();
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list_for_each_entry(pkt_dev, &t->if_list, list) {
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list_for_each_entry_rcu(pkt_dev, &t->if_list, list) {
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pktgen_stop_device(pkt_dev);
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}
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if_unlock(t);
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rcu_read_unlock();
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}
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/*
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@ -3220,8 +3220,6 @@ static void pktgen_rem_one_if(struct pktgen_thread *t)
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func_enter();
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if_lock(t);
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list_for_each_safe(q, n, &t->if_list) {
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cur = list_entry(q, struct pktgen_dev, list);
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@ -3235,8 +3233,6 @@ static void pktgen_rem_one_if(struct pktgen_thread *t)
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break;
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}
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if_unlock(t);
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}
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static void pktgen_rem_all_ifs(struct pktgen_thread *t)
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@ -3248,8 +3244,6 @@ static void pktgen_rem_all_ifs(struct pktgen_thread *t)
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/* Remove all devices, free mem */
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if_lock(t);
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list_for_each_safe(q, n, &t->if_list) {
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cur = list_entry(q, struct pktgen_dev, list);
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@ -3258,8 +3252,6 @@ static void pktgen_rem_all_ifs(struct pktgen_thread *t)
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pktgen_remove_device(t, cur);
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}
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if_unlock(t);
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}
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static void pktgen_rem_thread(struct pktgen_thread *t)
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@ -3407,10 +3399,10 @@ static int pktgen_thread_worker(void *arg)
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pr_debug("starting pktgen/%d: pid=%d\n", cpu, task_pid_nr(current));
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set_current_state(TASK_INTERRUPTIBLE);
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set_freezable();
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__set_current_state(TASK_RUNNING);
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while (!kthread_should_stop()) {
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pkt_dev = next_to_run(t);
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@ -3424,8 +3416,6 @@ static int pktgen_thread_worker(void *arg)
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continue;
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}
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__set_current_state(TASK_RUNNING);
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if (likely(pkt_dev)) {
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pktgen_xmit(pkt_dev);
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@ -3456,9 +3446,8 @@ static int pktgen_thread_worker(void *arg)
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}
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try_to_freeze();
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set_current_state(TASK_INTERRUPTIBLE);
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}
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set_current_state(TASK_INTERRUPTIBLE);
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pr_debug("%s stopping all device\n", t->tsk->comm);
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pktgen_stop(t);
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@ -3485,8 +3474,8 @@ static struct pktgen_dev *pktgen_find_dev(struct pktgen_thread *t,
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struct pktgen_dev *p, *pkt_dev = NULL;
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size_t len = strlen(ifname);
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if_lock(t);
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list_for_each_entry(p, &t->if_list, list)
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rcu_read_lock();
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list_for_each_entry_rcu(p, &t->if_list, list)
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if (strncmp(p->odevname, ifname, len) == 0) {
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if (p->odevname[len]) {
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if (exact || p->odevname[len] != '@')
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@ -3496,7 +3485,7 @@ static struct pktgen_dev *pktgen_find_dev(struct pktgen_thread *t,
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break;
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}
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if_unlock(t);
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rcu_read_unlock();
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pr_debug("find_dev(%s) returning %p\n", ifname, pkt_dev);
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return pkt_dev;
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}
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@ -3510,6 +3499,12 @@ static int add_dev_to_thread(struct pktgen_thread *t,
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{
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int rv = 0;
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/* This function cannot be called concurrently, as its called
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* under pktgen_thread_lock mutex, but it can run from
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* userspace on another CPU than the kthread. The if_lock()
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* is used here to sync with concurrent instances of
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* _rem_dev_from_if_list() invoked via kthread, which is also
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* updating the if_list */
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if_lock(t);
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if (pkt_dev->pg_thread) {
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@ -3518,9 +3513,9 @@ static int add_dev_to_thread(struct pktgen_thread *t,
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goto out;
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}
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list_add(&pkt_dev->list, &t->if_list);
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pkt_dev->pg_thread = t;
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pkt_dev->running = 0;
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pkt_dev->pg_thread = t;
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list_add_rcu(&pkt_dev->list, &t->if_list);
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out:
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if_unlock(t);
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@ -3675,11 +3670,13 @@ static void _rem_dev_from_if_list(struct pktgen_thread *t,
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struct list_head *q, *n;
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struct pktgen_dev *p;
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if_lock(t);
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list_for_each_safe(q, n, &t->if_list) {
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p = list_entry(q, struct pktgen_dev, list);
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if (p == pkt_dev)
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list_del(&p->list);
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list_del_rcu(&p->list);
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}
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if_unlock(t);
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}
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static int pktgen_remove_device(struct pktgen_thread *t,
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@ -3699,20 +3696,22 @@ static int pktgen_remove_device(struct pktgen_thread *t,
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pkt_dev->odev = NULL;
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}
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/* And update the thread if_list */
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_rem_dev_from_if_list(t, pkt_dev);
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/* Remove proc before if_list entry, because add_device uses
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* list to determine if interface already exist, avoid race
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* with proc_create_data() */
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if (pkt_dev->entry)
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proc_remove(pkt_dev->entry);
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/* And update the thread if_list */
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_rem_dev_from_if_list(t, pkt_dev);
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#ifdef CONFIG_XFRM
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free_SAs(pkt_dev);
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#endif
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vfree(pkt_dev->flows);
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if (pkt_dev->page)
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put_page(pkt_dev->page);
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kfree(pkt_dev);
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kfree_rcu(pkt_dev, rcu);
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return 0;
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}
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@ -3812,6 +3811,7 @@ static void __exit pg_cleanup(void)
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{
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unregister_netdevice_notifier(&pktgen_notifier_block);
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unregister_pernet_subsys(&pg_net_ops);
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/* Don't need rcu_barrier() due to use of kfree_rcu() */
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}
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module_init(pg_init);
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||||
|
|
|
|||
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