libvirt/src/util/virnetdevbandwidth.c

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/*
* Copyright (C) 2009-2012 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*
* Authors:
* Michal Privoznik <mprivozn@redhat.com>
* Daniel P. Berrange <berrange@redhat.com>
*/
#include <config.h>
#include "virnetdevbandwidth.h"
#include "vircommand.h"
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#include "viralloc.h"
#include "virerror.h"
#define VIR_FROM_THIS VIR_FROM_NONE
void
virNetDevBandwidthFree(virNetDevBandwidthPtr def)
{
if (!def)
return;
VIR_FREE(def->in);
VIR_FREE(def->out);
VIR_FREE(def);
}
/**
* virNetDevBandwidthSet:
* @ifname: on which interface
* @bandwidth: rates to set (may be NULL)
* @hierarchical_class: whether to create hierarchical class
*
* This function enables QoS on specified interface
* and set given traffic limits for both, incoming
* and outgoing traffic. Any previous setting get
* overwritten. If @hierarchical_class is TRUE, create
* hierarchical class. It is used to guarantee minimal
* throughput ('floor' attribute in NIC).
*
* Return 0 on success, -1 otherwise.
*/
int
virNetDevBandwidthSet(const char *ifname,
virNetDevBandwidthPtr bandwidth,
bool hierarchical_class)
{
int ret = -1;
virCommandPtr cmd = NULL;
char *average = NULL;
char *peak = NULL;
char *burst = NULL;
if (!bandwidth) {
/* nothing to be enabled */
ret = 0;
goto cleanup;
}
virNetDevBandwidthClear(ifname);
if (bandwidth->in && bandwidth->in->average) {
if (virAsprintf(&average, "%llukbps", bandwidth->in->average) < 0)
goto cleanup;
if (bandwidth->in->peak &&
(virAsprintf(&peak, "%llukbps", bandwidth->in->peak) < 0))
goto cleanup;
if (bandwidth->in->burst &&
(virAsprintf(&burst, "%llukb", bandwidth->in->burst) < 0))
goto cleanup;
cmd = virCommandNew(TC);
virCommandAddArgList(cmd, "qdisc", "add", "dev", ifname, "root",
"handle", "1:", "htb", "default",
hierarchical_class ? "2" : "1", NULL);
if (virCommandRun(cmd, NULL) < 0)
goto cleanup;
/* If we are creating a hierarchical class, all non guaranteed traffic
* goes to the 1:2 class which will adjust 'rate' dynamically as NICs
* with guaranteed throughput are plugged and unplugged. Class 1:1
* exists so we don't exceed the maximum limit for the network. For each
* NIC with guaranteed throughput a separate classid will be created.
* NB '1:' is just a shorter notation of '1:0'.
*
* To get a picture how this works:
*
* +-----+ +---------+ +-----------+ +-----------+ +-----+
* | | | qdisc | | class 1:1 | | class 1:2 | | |
* | NIC | | def 1:2 | | rate | | rate | | sfq |
* | | --> | | --> | peak | -+-> | peak | --> | |
* +-----+ +---------+ +-----------+ | +-----------+ +-----+
* |
* | +-----------+ +-----+
* | | class 1:3 | | |
* | | rate | | sfq |
* +-> | peak | --> | |
* | +-----------+ +-----+
* ...
* | +-----------+ +-----+
* | | class 1:n | | |
* | | rate | | sfq |
* +-> | peak | --> | |
* +-----------+ +-----+
*
* After the routing decision, when is it clear a packet is to be sent
* via a particular NIC, it is sent to the root qdisc (queueing
* discipline). In this case HTB (Hierarchical Token Bucket). It has
* only one direct child class (with id 1:1) which shapes the overall
* rate that is sent through the NIC. This class has at least one child
* (1:2) which is meant for all non-privileged (non guaranteed) traffic
* from all domains. Then, for each interface with guaranteed
* throughput, a separate class (1:n) is created. Imagine a class is a
* box. Whenever a packet ends up in a class it is stored in this box
* until the kernel sends it, then it is removed from box. Packets are
* placed into boxes based on rules (filters) - e.g. depending on
* destination IP/MAC address. If there is no rule to be applied, the
* root qdisc has a default where such packets go (1:2 in this case).
* Packets come in over and over again and boxes get filled more and
* more. Imagine that kernel sends packets just once a second. So it
* starts to traverse through this tree. It starts with the root qdisc
* and through 1:1 it gets to 1:2. It sends packets up to 1:2's 'rate'.
* Then it moves to 1:3 and again sends packets up to 1:3's 'rate'. The
* whole process is repeated until 1:n is processed. So now we have
* ensured each class its guaranteed bandwidth. If the sum of sent data
* doesn't exceed the 'rate' in 1:1 class, we can go further and send
* more packets. The rest of available bandwidth is distributed to the
* 1:2,1:3...1:n classes by ratio of their 'rate'. As soon as the root
* 'rate' limit is reached or there are no more packets to send, we stop
* sending and wait another second. Each class has an SFQ qdisc which
* shuffles packets in boxes stochastically, so one sender cannot
* starve others.
*
* Therefore, whenever we want to plug in a new guaranteed interface, we
* need to create a new class and adjust the 'rate' of the 1:2 class.
* When unplugging we do the exact opposite - remove the associated
* class, and adjust the 'rate'.
*
* This description is rather long, but it is still a good idea to read
* it before you dig into the code.
*/
if (hierarchical_class) {
virCommandFree(cmd);
cmd = virCommandNew(TC);
virCommandAddArgList(cmd, "class", "add", "dev", ifname, "parent",
"1:", "classid", "1:1", "htb", "rate", average,
"ceil", peak ? peak : average, NULL);
if (virCommandRun(cmd, NULL) < 0)
goto cleanup;
}
virCommandFree(cmd);
cmd = virCommandNew(TC);
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virCommandAddArgList(cmd,"class", "add", "dev", ifname, "parent",
hierarchical_class ? "1:1" : "1:", "classid",
hierarchical_class ? "1:2" : "1:1", "htb",
"rate", average, NULL);
if (peak)
virCommandAddArgList(cmd, "ceil", peak, NULL);
if (burst)
virCommandAddArgList(cmd, "burst", burst, NULL);
if (virCommandRun(cmd, NULL) < 0)
goto cleanup;
virCommandFree(cmd);
cmd = virCommandNew(TC);
virCommandAddArgList(cmd, "qdisc", "add", "dev", ifname, "parent",
hierarchical_class ? "1:2" : "1:1",
"handle", "2:", "sfq", "perturb",
"10", NULL);
if (virCommandRun(cmd, NULL) < 0)
goto cleanup;
virCommandFree(cmd);
cmd = virCommandNew(TC);
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virCommandAddArgList(cmd,"filter", "add", "dev", ifname, "parent",
"1:0", "protocol", "ip", "handle", "1", "fw",
"flowid", "1", NULL);
if (virCommandRun(cmd, NULL) < 0)
goto cleanup;
VIR_FREE(average);
VIR_FREE(peak);
VIR_FREE(burst);
}
if (bandwidth->out) {
if (virAsprintf(&average, "%llukbps", bandwidth->out->average) < 0)
goto cleanup;
if (virAsprintf(&burst, "%llukb", bandwidth->out->burst ?
bandwidth->out->burst : bandwidth->out->average) < 0)
goto cleanup;
virCommandFree(cmd);
cmd = virCommandNew(TC);
virCommandAddArgList(cmd, "qdisc", "add", "dev", ifname,
"ingress", NULL);
if (virCommandRun(cmd, NULL) < 0)
goto cleanup;
virCommandFree(cmd);
cmd = virCommandNew(TC);
virCommandAddArgList(cmd, "filter", "add", "dev", ifname, "parent",
"ffff:", "protocol", "ip", "u32", "match", "ip",
"src", "0.0.0.0/0", "police", "rate", average,
Fix vm's outbound traffic control problem Hello, This is a patch to fix vm's outbound traffic control problem. Currently, vm's outbound traffic control by libvirt doesn't go well. This problem was previously discussed at libvir-list ML, however it seems that there isn't still any answer to the problem. http://www.redhat.com/archives/libvir-list/2011-August/msg00333.html I measured Guest(with virtio-net) to Host TCP throughput with the command "netperf -H". Here are the outbound QoS parameters and the results. outbound average rate[kilobytes/s] : Guest to Host throughput[Mbit/s] ====================================================================== 1024 (8Mbit/s) : 4.56 2048 (16Mbit/s) : 3.29 4096 (32Mbit/s) : 3.35 8192 (64Mbit/s) : 3.95 16384 (128Mbit/s) : 4.08 32768 (256Mbit/s) : 3.94 65536 (512Mbit/s) : 3.23 The outbound traffic goes down unreasonably and is even not controled. The cause of this problem is too large mtu value in "tc filter" command run by libvirt. The command uses burst value to set mtu and the burst is equal to average rate value if it's not set. This value is too large. For example if the average rate is set to 1024 kilobytes/s, the mtu value is set to 1024 kilobytes. That's too large compared to the size of network packets. Here libvirt applies tc ingress filter to Host's vnet(tun) device. Tc ingress filter is implemented with TBF(Token Buckets Filter) algorithm. TBF uses mtu value to calculate the amount of token consumed by each packet. With too large mtu value, the token consumption rate is set too large. This leads to token starvation and deterioration of TCP throughput. Then, should we use the default mtu value 2 kilobytes? The anser is No, because Guest with virtio-net device uses 65536 bytes as mtu to transmit packets to Host, and the tc filter with the default mtu value 2k drops packets whose size is larger than 2k. So, the most packets is droped and again leads to deterioration of TCP throughput. The appropriate mtu value is 65536 bytes which is equal to the maximum value of network interface device defined in <linux/netdevice.h>. The value is not so large that it causes token starvation and not so small that it drops most packets. Therefore this patch set the mtu value to 64kb(== 65535 bytes). Again, here are the outbound QoS parameters and the TCP throughput with the libvirt patched. outbound average rate[kilobytes/s] : Guest to Host throughput[Mbit/s] ====================================================================== 1024 (8Mbit/s) : 8.22 2048 (16Mbit/s) : 16.42 4096 (32Mbit/s) : 32.93 8192 (64Mbit/s) : 66.85 16384 (128Mbit/s) : 133.88 32768 (256Mbit/s) : 271.01 65536 (512Mbit/s) : 547.32 The outbound traffic conforms to the given limit. Thank you, Signed-off-by: Eiichi Tsukata <eiichi.tsukata.xh@hitachi.com>
2012-06-29 06:09:16 +00:00
"burst", burst, "mtu", "64kb", "drop", "flowid",
":1", NULL);
if (virCommandRun(cmd, NULL) < 0)
goto cleanup;
}
ret = 0;
cleanup:
virCommandFree(cmd);
VIR_FREE(average);
VIR_FREE(peak);
VIR_FREE(burst);
return ret;
}
/**
* virNetDevBandwidthClear:
* @ifname: on which interface
*
* This function tries to disable QoS on specified interface
* by deleting root and ingress qdisc. However, this may fail
* if we try to remove the default one.
*
* Return 0 on success, -1 otherwise.
*/
int
virNetDevBandwidthClear(const char *ifname)
{
int ret = 0;
int dummy; /* for ignoring the exit status */
virCommandPtr cmd = NULL;
cmd = virCommandNew(TC);
virCommandAddArgList(cmd, "qdisc", "del", "dev", ifname, "root", NULL);
if (virCommandRun(cmd, &dummy) < 0)
ret = -1;
virCommandFree(cmd);
cmd = virCommandNew(TC);
virCommandAddArgList(cmd, "qdisc", "del", "dev", ifname, "ingress", NULL);
if (virCommandRun(cmd, &dummy) < 0)
ret = -1;
virCommandFree(cmd);
return ret;
}
/*
* virNetDevBandwidthCopy:
* @dest: destination
* @src: source (may be NULL)
*
* Returns -1 on OOM error (which gets reported),
* 0 otherwise.
*/
int
virNetDevBandwidthCopy(virNetDevBandwidthPtr *dest,
const virNetDevBandwidthPtr src)
{
int ret = -1;
*dest = NULL;
if (!src) {
/* nothing to be copied */
return 0;
}
if (VIR_ALLOC(*dest) < 0) {
virReportOOMError();
goto cleanup;
}
if (src->in) {
if (VIR_ALLOC((*dest)->in) < 0) {
virReportOOMError();
goto cleanup;
}
memcpy((*dest)->in, src->in, sizeof(*src->in));
}
if (src->out) {
if (VIR_ALLOC((*dest)->out) < 0) {
virReportOOMError();
VIR_FREE((*dest)->in);
goto cleanup;
}
memcpy((*dest)->out, src->out, sizeof(*src->out));
}
ret = 0;
cleanup:
if (ret < 0) {
virNetDevBandwidthFree(*dest);
*dest = NULL;
}
return ret;
}
bool
virNetDevBandwidthEqual(virNetDevBandwidthPtr a,
virNetDevBandwidthPtr b)
{
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if (!a && !b)
return true;
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if (!a || !b)
return false;
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/* in */
if (a->in->average != b->in->average ||
a->in->peak != b->in->peak ||
a->in->burst != b->in->burst)
return false;
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/*out*/
if (a->out->average != b->out->average ||
a->out->peak != b->out->peak ||
a->out->burst != b->out->burst)
return false;
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return true;
}
/*
* virNetDevBandwidthPlug:
* @brname: name of the bridge
* @net_bandwidth: QoS settings on @brname
* @ifmac: MAC of interface
* @bandwidth: QoS settings for interface
* @id: unique ID (MUST be greater than 2)
*
* Set bridge part of interface QoS settings, e.g. guaranteed
* bandwidth. @id is an unique ID (among @brname) from which
* other identifiers for class, qdisc and filter are derived.
* However, two classes were already set up (by
* virNetDevBandwidthSet). That's why this @id MUST be greater
* than 2. You may want to keep passed @id, as it is used later
* by virNetDevBandwidthUnplug.
*
* Returns:
* 0 if QoS set successfully
* -1 otherwise.
*/
int
virNetDevBandwidthPlug(const char *brname,
virNetDevBandwidthPtr net_bandwidth,
const virMacAddrPtr ifmac_ptr,
virNetDevBandwidthPtr bandwidth,
unsigned int id)
{
int ret = -1;
virCommandPtr cmd = NULL;
char *class_id = NULL;
char *qdisc_id = NULL;
char *filter_id = NULL;
char *floor = NULL;
char *ceil = NULL;
unsigned char ifmac[VIR_MAC_BUFLEN];
char ifmacStr[VIR_MAC_STRING_BUFLEN];
char *mac[2] = {NULL, NULL};
if (id <= 2) {
virReportError(VIR_ERR_INTERNAL_ERROR, _("Invalid class ID %d"), id);
return -1;
}
virMacAddrGetRaw(ifmac_ptr, ifmac);
virMacAddrFormat(ifmac_ptr, ifmacStr);
if (!net_bandwidth || !net_bandwidth->in) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
_("Bridge '%s' has no QoS set, therefore "
"unable to set 'floor' on '%s'"),
brname, ifmacStr);
return -1;
}
if (virAsprintf(&class_id, "1:%x", id) < 0 ||
virAsprintf(&qdisc_id, "%x:", id) < 0 ||
virAsprintf(&filter_id, "%u", id) < 0 ||
virAsprintf(&mac[0], "0x%02x%02x%02x%02x", ifmac[2],
ifmac[3], ifmac[4], ifmac[5]) < 0 ||
virAsprintf(&mac[1], "0x%02x%02x", ifmac[0], ifmac[1]) < 0 ||
virAsprintf(&floor, "%llukbps", bandwidth->in->floor) < 0 ||
virAsprintf(&ceil, "%llukbps", net_bandwidth->in->peak ?
net_bandwidth->in->peak :
net_bandwidth->in->average) < 0) {
virReportOOMError();
goto cleanup;
}
cmd = virCommandNew(TC);
virCommandAddArgList(cmd, "class", "add", "dev", brname, "parent", "1:1",
"classid", class_id, "htb", "rate", floor,
"ceil", ceil, NULL);
if (virCommandRun(cmd, NULL) < 0)
goto cleanup;
virCommandFree(cmd);
cmd = virCommandNew(TC);
virCommandAddArgList(cmd, "qdisc", "add", "dev", brname, "parent",
class_id, "handle", qdisc_id, "sfq", "perturb",
"10", NULL);
if (virCommandRun(cmd, NULL) < 0)
goto cleanup;
virCommandFree(cmd);
cmd = virCommandNew(TC);
/* Okay, this not nice. But since libvirt does not know anything about
* interface IP address(es), and tc fw filter simply refuse to use ebtables
* marks, we need to use u32 selector to match MAC address.
* If libvirt will ever know something, remove this FIXME
*/
virCommandAddArgList(cmd, "filter", "add", "dev", brname, "protocol", "ip",
"prio", filter_id, "u32",
"match", "u16", "0x0800", "0xffff", "at", "-2",
"match", "u32", mac[0], "0xffffffff", "at", "-12",
"match", "u16", mac[1], "0xffff", "at", "-14",
"flowid", class_id, NULL);
if (virCommandRun(cmd, NULL) < 0)
goto cleanup;
ret = 0;
cleanup:
VIR_FREE(mac[1]);
VIR_FREE(mac[0]);
VIR_FREE(ceil);
VIR_FREE(floor);
VIR_FREE(filter_id);
VIR_FREE(qdisc_id);
VIR_FREE(class_id);
virCommandFree(cmd);
return ret;
}
/*
* virNetDevBandwidthUnplug:
* @brname: from which bridge are we unplugging
* @id: unique identifier (MUST be greater than 2)
*
* Remove QoS settings from bridge.
*
* Returns 0 on success, -1 otherwise.
*/
int
virNetDevBandwidthUnplug(const char *brname,
unsigned int id)
{
int ret = -1;
int cmd_ret = 0;
virCommandPtr cmd = NULL;
char *class_id = NULL;
char *qdisc_id = NULL;
char *filter_id = NULL;
if (id <= 2) {
virReportError(VIR_ERR_INTERNAL_ERROR, _("Invalid class ID %d"), id);
return -1;
}
if (virAsprintf(&class_id, "1:%x", id) < 0 ||
virAsprintf(&qdisc_id, "%x:", id) < 0 ||
virAsprintf(&filter_id, "%u", id) < 0) {
virReportOOMError();
goto cleanup;
}
cmd = virCommandNew(TC);
virCommandAddArgList(cmd, "qdisc", "del", "dev", brname,
"handle", qdisc_id, NULL);
/* Don't threat tc errors as fatal, but
* try to remove as much as possible */
if (virCommandRun(cmd, &cmd_ret) < 0)
goto cleanup;
virCommandFree(cmd);
cmd = virCommandNew(TC);
virCommandAddArgList(cmd, "filter", "del", "dev", brname,
"prio", filter_id, NULL);
if (virCommandRun(cmd, &cmd_ret) < 0)
goto cleanup;
cmd = virCommandNew(TC);
virCommandAddArgList(cmd, "class", "del", "dev", brname,
"classid", class_id, NULL);
if (virCommandRun(cmd, &cmd_ret) < 0)
goto cleanup;
ret = 0;
cleanup:
VIR_FREE(filter_id);
VIR_FREE(qdisc_id);
VIR_FREE(class_id);
virCommandFree(cmd);
return ret;
}
/**
* virNetDevBandwidthUpdateRate:
* @ifname: interface name
* @classid: ID of class to update
* @new_rate: new rate
*
* This function updates the 'rate' attribute of HTB class.
* It can be used whenever a new interface is plugged to a
* bridge to adjust average throughput of non guaranteed
* NICs.
*
* Returns 0 on success, -1 otherwise.
*/
int
virNetDevBandwidthUpdateRate(const char *ifname,
const char *class_id,
virNetDevBandwidthPtr bandwidth,
unsigned long long new_rate)
{
int ret = -1;
virCommandPtr cmd = NULL;
char *rate = NULL;
char *ceil = NULL;
if (virAsprintf(&rate, "%llukbps", new_rate) < 0 ||
virAsprintf(&ceil, "%llukbps", bandwidth->in->peak ?
bandwidth->in->peak :
bandwidth->in->average) < 0) {
virReportOOMError();
goto cleanup;
}
cmd = virCommandNew(TC);
virCommandAddArgList(cmd, "class", "change", "dev", ifname,
"classid", class_id, "htb", "rate", rate,
"ceil", ceil, NULL);
if (virCommandRun(cmd, NULL) < 0)
goto cleanup;
ret = 0;
cleanup:
virCommandFree(cmd);
VIR_FREE(rate);
VIR_FREE(ceil);
return ret;
}