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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH] Credit Limiting Backend Network Interfaces
Hi,
Attached is a patch which allows a domain's network transmission to be
limited, to a certain credit of bytes every predefined period.
The virtual interface of a domain can be limited using the command
xm vif-limit [domain id] [vif number] [credit in bytes] [period in
uSecs]
e.g. to limit vif2.1 to 2Mb every second:
xm vif-limit 2 1 2000000 1000000
As Keir mentioned, it uses the jiffy timer, so is not very accurate
time-wise. It should be ok as long as you don't set the period below
about 10 mSecs. Thoughts are welcome as to how this accuracy can be
increase.
In netback.c I moved the incrementing of req_cons below the credit
check, so that it is only incremented if the interface has enough
credit. I wasn't sure however, if the memory barrier was needed after
this increment, before the request copy, or in both placed. I've left
it in both places, which seems to work well enough, but I'm not sure if
I've now added an unnecessary memory barrier call.
The patch is made against Xen 2.0.4, and seems to work well enough for
me. Let me know what you think.
Thanks
Ross
diff -Naur xen-2.0/linux-2.6.10-xen-sparse/drivers/xen/netback/common.h
xen_creditlimit/linux-2.6.10-xen-sparse/drivers/xen/netback/common.h
--- xen-2.0/linux-2.6.10-xen-sparse/drivers/xen/netback/common.h
2005-02-04 13:38:30.000000000 +0000
+++ xen_creditlimit/linux-2.6.10-xen-sparse/drivers/xen/netback/common.h
2005-03-02 12:09:08.439496264 +0000
@@ -76,6 +76,7 @@
void netif_create(netif_be_create_t *create);
void netif_destroy(netif_be_destroy_t *destroy);
+void netif_creditlimit(netif_be_creditlimit_t *creditlimit);
void netif_connect(netif_be_connect_t *connect);
int netif_disconnect(netif_be_disconnect_t *disconnect, u8 rsp_id);
void netif_disconnect_complete(netif_t *netif);
diff -Naur xen-2.0/linux-2.6.10-xen-sparse/drivers/xen/netback/control.c
xen_creditlimit/linux-2.6.10-xen-sparse/drivers/xen/netback/control.c
--- xen-2.0/linux-2.6.10-xen-sparse/drivers/xen/netback/control.c
2005-02-04 13:38:28.000000000 +0000
+++
xen_creditlimit/linux-2.6.10-xen-sparse/drivers/xen/netback/control.c
2005-03-02 12:11:04.247890712 +0000
@@ -21,12 +21,17 @@
if ( msg->length != sizeof(netif_be_destroy_t) )
goto parse_error;
netif_destroy((netif_be_destroy_t *)&msg->msg[0]);
- break;
+ break;
+ case CMSG_NETIF_BE_CREDITLIMIT:
+ if ( msg->length != sizeof(netif_be_creditlimit_t) )
+ goto parse_error;
+ netif_creditlimit((netif_be_creditlimit_t *)&msg->msg[0]);
+ break;
case CMSG_NETIF_BE_CONNECT:
if ( msg->length != sizeof(netif_be_connect_t) )
goto parse_error;
netif_connect((netif_be_connect_t *)&msg->msg[0]);
- break;
+ break;
case CMSG_NETIF_BE_DISCONNECT:
if ( msg->length != sizeof(netif_be_disconnect_t) )
goto parse_error;
diff -Naur
xen-2.0/linux-2.6.10-xen-sparse/drivers/xen/netback/interface.c
xen_creditlimit/linux-2.6.10-xen-sparse/drivers/xen/netback/interface.c
--- xen-2.0/linux-2.6.10-xen-sparse/drivers/xen/netback/interface.c
2005-02-04 13:38:34.000000000 +0000
+++
xen_creditlimit/linux-2.6.10-xen-sparse/drivers/xen/netback/interface.c
2005-03-02 12:12:28.212126208 +0000
@@ -140,7 +140,7 @@
netif->credit_bytes = netif->remaining_credit = ~0UL;
netif->credit_usec = 0UL;
- /*init_ac_timer(&new_vif->credit_timeout);*/
+ init_timer(&netif->credit_timeout);
pnetif = &netif_hash[NETIF_HASH(domid, handle)];
while ( *pnetif != NULL )
@@ -223,6 +223,36 @@
destroy->status = NETIF_BE_STATUS_OKAY;
}
+void netif_creditlimit(netif_be_creditlimit_t *creditlimit)
+{
+ domid_t domid = creditlimit->domid;
+ unsigned int handle = creditlimit->netif_handle;
+ netif_t *netif;
+
+ netif = netif_find_by_handle(domid, handle);
+ if ( unlikely(netif == NULL) )
+ {
+ DPRINTK("netif_creditlimit attempted for non-existent netif"
+ " (%u,%u)\n", creditlimit->domid,
creditlimit->netif_handle);
+ creditlimit->status = NETIF_BE_STATUS_INTERFACE_NOT_FOUND;
+ return;
+ }
+
+ /* set the credit limit (reset remaining credit to new limit) */
+ netif->credit_bytes = netif->remaining_credit =
creditlimit->credit_bytes;
+ netif->credit_usec = creditlimit->period_usec;
+
+ if ( netif->status == CONNECTED )
+ {
+ /* schedule work so that any packets waiting under previous
+ credit limit are dealt with (acts like a replenishment
point) */
+ netif->credit_timeout.expires = jiffies;
+ netif_schedule_work(netif);
+ }
+
+ creditlimit->status = NETIF_BE_STATUS_OKAY;
+}
+
void netif_connect(netif_be_connect_t *connect)
{
domid_t domid = connect->domid;
diff -Naur xen-2.0/linux-2.6.10-xen-sparse/drivers/xen/netback/netback.c
xen_creditlimit/linux-2.6.10-xen-sparse/drivers/xen/netback/netback.c
--- xen-2.0/linux-2.6.10-xen-sparse/drivers/xen/netback/netback.c
2005-02-04 13:38:32.000000000 +0000
+++
xen_creditlimit/linux-2.6.10-xen-sparse/drivers/xen/netback/netback.c
2005-03-02 12:14:32.040301464 +0000
@@ -379,14 +379,13 @@
remove_from_net_schedule_list(netif);
}
-#if 0
+
static void tx_credit_callback(unsigned long data)
{
netif_t *netif = (netif_t *)data;
netif->remaining_credit = netif->credit_bytes;
netif_schedule_work(netif);
}
-#endif
static void net_tx_action(unsigned long unused)
{
@@ -470,8 +469,6 @@
continue;
}
- netif->tx->req_cons = ++netif->tx_req_cons;
-
/*
* 1. Ensure that we see the request when we copy it.
* 2. Ensure that frontend sees updated req_cons before we
check
@@ -482,30 +479,36 @@
memcpy(&txreq, &netif->tx->ring[MASK_NETIF_TX_IDX(i)].req,
sizeof(txreq));
-#if 0
/* Credit-based scheduling. */
- if ( tx.size > netif->remaining_credit )
+ if ( txreq.size > netif->remaining_credit )
{
- s_time_t now = NOW(), next_credit =
- netif->credit_timeout.expires +
MICROSECS(netif->credit_usec);
- if ( next_credit <= now )
+ unsigned long now = jiffies;
+ unsigned long next_credit = netif->credit_timeout.expires
+ + msecs_to_jiffies(netif->credit_usec / 1000);
+ if ( !time_after(next_credit,now) )
{
netif->credit_timeout.expires = now;
netif->remaining_credit = netif->credit_bytes;
}
else
{
- netif->remaining_credit = 0;
- netif->credit_timeout.expires = next_credit;
- netif->credit_timeout.data = (unsigned long)netif;
- netif->credit_timeout.function = tx_credit_callback;
- netif->credit_timeout.cpu = smp_processor_id();
- add_ac_timer(&netif->credit_timeout);
- break;
+ if (!timer_pending(&netif->credit_timeout)) {
+ netif->remaining_credit = 0;
+ netif->credit_timeout.expires = next_credit;
+ netif->credit_timeout.data = (unsigned
long)netif;
+ netif->credit_timeout.function = tx_credit_callback;
+ add_timer_on(&netif->credit_timeout,
smp_processor_id());
+ } /* else already set to replenish credit */
+ break;
}
}
- netif->remaining_credit -= tx.size;
-#endif
+ if (netif->remaining_credit > txreq.size)
+ netif->remaining_credit -= txreq.size;
+ else
+ netif->remaining_credit = 0; /* prevent rollover */
+
+ netif->tx->req_cons = ++netif->tx_req_cons;
+ mb();
netif_schedule_work(netif);
diff -Naur xen-2.0/tools/python/xen/lowlevel/xu/xu.c
xen_creditlimit/tools/python/xen/lowlevel/xu/xu.c
--- xen-2.0/tools/python/xen/lowlevel/xu/xu.c 2005-02-04
13:38:30.000000000 +0000
+++ xen_creditlimit/tools/python/xen/lowlevel/xu/xu.c 2005-02-27
13:22:36.000000000 +0000
@@ -462,6 +462,13 @@
C2P(netif_be_destroy_t, netif_handle, Int, Long);
C2P(netif_be_destroy_t, status, Int, Long);
return dict;
+ case TYPE(CMSG_NETIF_BE, CMSG_NETIF_BE_CREDITLIMIT):
+ C2P(netif_be_creditlimit_t, domid, Int, Long);
+ C2P(netif_be_creditlimit_t, netif_handle, Int, Long);
+ C2P(netif_be_creditlimit_t, credit_bytes, Int, Long);
+ C2P(netif_be_creditlimit_t, period_usec, Int, Long);
+ C2P(netif_be_creditlimit_t, status, Int, Long);
+ return dict;
case TYPE(CMSG_NETIF_BE, CMSG_NETIF_BE_CONNECT):
C2P(netif_be_connect_t, domid, Int, Long);
C2P(netif_be_connect_t, netif_handle, Int, Long);
@@ -628,6 +635,12 @@
P2C(netif_be_destroy_t, domid, u32);
P2C(netif_be_destroy_t, netif_handle, u32);
break;
+ case TYPE(CMSG_NETIF_BE, CMSG_NETIF_BE_CREDITLIMIT):
+ P2C(netif_be_creditlimit_t, domid, u32);
+ P2C(netif_be_creditlimit_t, netif_handle, u32);
+ P2C(netif_be_creditlimit_t, credit_bytes, u32);
+ P2C(netif_be_creditlimit_t, period_usec, u32);
+ break;
case TYPE(CMSG_NETIF_BE, CMSG_NETIF_BE_CONNECT):
P2C(netif_be_connect_t, domid, u32);
P2C(netif_be_connect_t, netif_handle, u32);
diff -Naur xen-2.0/tools/python/xen/xend/server/messages.py
xen_creditlimit/tools/python/xen/xend/server/messages.py
--- xen-2.0/tools/python/xen/xend/server/messages.py 2005-02-04
13:38:31.000000000 +0000
+++ xen_creditlimit/tools/python/xen/xend/server/messages.py
2005-03-02 12:15:43.792393488 +0000
@@ -150,6 +150,7 @@
CMSG_NETIF_BE_DESTROY = 1
CMSG_NETIF_BE_CONNECT = 2
CMSG_NETIF_BE_DISCONNECT = 3
+CMSG_NETIF_BE_CREDITLIMIT = 4
CMSG_NETIF_BE_DRIVER_STATUS = 32
NETIF_INTERFACE_STATUS_CLOSED = 0 #/* Interface doesn't exist.
*/
@@ -173,6 +174,9 @@
'netif_be_destroy_t':
(CMSG_NETIF_BE, CMSG_NETIF_BE_DESTROY),
+ 'netif_be_creditlimit_t':
+ (CMSG_NETIF_BE, CMSG_NETIF_BE_CREDITLIMIT),
+
'netif_be_driver_status_t':
(CMSG_NETIF_BE, CMSG_NETIF_BE_DRIVER_STATUS),
diff -Naur xen-2.0/tools/python/xen/xend/server/netif.py
xen_creditlimit/tools/python/xen/xend/server/netif.py
--- xen-2.0/tools/python/xen/xend/server/netif.py 2005-02-04
13:38:34.000000000 +0000
+++ xen_creditlimit/tools/python/xen/xend/server/netif.py
2005-02-28 12:45:11.000000000 +0000
@@ -326,7 +326,21 @@
vif = val['netif_handle']
self.status = NETIF_INTERFACE_STATUS_CONNECTED
self.reportStatus()
-
+
+ def send_be_creditlimit(self, credit, period):
+ msg = packMsg('netif_be_creditlimit_t',
+ { 'domid' : self.controller.dom,
+ 'netif_handle' : self.vif,
+ 'credit_bytes' : credit,
+ 'period_usec' : period })
+ d = defer.Deferred()
+ d.addCallback(self.respond_be_creditlimit)
+ self.getBackendInterface().writeRequest(msg, response=d)
+
+ def respond_be_creditlimit(self, msg):
+ val = unpackMsg('netif_be_creditlimit_t', msg)
+ return self
+
def reportStatus(self, resp=0):
msg = packMsg('netif_fe_interface_status_t',
{ 'handle' : self.vif,
@@ -410,6 +424,15 @@
d = dev.attach()
return d
+ def limitDevice(self, vif, credit, period):
+ if vif not in self.devices:
+ raise XendError('device does not exist for credit limit:
vif'
+ + str(self.dom) + '.' + str(vif))
+
+ dev = self.devices[vif]
+ d = dev.send_be_creditlimit(credit, period)
+ return d
+
def recv_fe_driver_status(self, msg, req):
if not req: return
print
diff -Naur xen-2.0/tools/python/xen/xend/server/SrvDomain.py
xen_creditlimit/tools/python/xen/xend/server/SrvDomain.py
--- xen-2.0/tools/python/xen/xend/server/SrvDomain.py 2005-02-04
13:38:37.000000000 +0000
+++ xen_creditlimit/tools/python/xen/xend/server/SrvDomain.py
2005-02-27 16:02:46.000000000 +0000
@@ -164,6 +164,15 @@
d = fn(req.args, {'dom': self.dom.id})
return d
+ def op_vif_credit_limit(self, op, req):
+ fn = FormFn(self.xd.domain_vif_credit_limit,
+ [['dom', 'str'],
+ ['vif', 'int'],
+ ['credit', 'int'],
+ ['period', 'int']])
+ val = fn(req.args, {'dom': self.dom.id})
+ return val
+
def op_vifs(self, op, req):
devs = self.xd.domain_vif_ls(self.dom.id)
return [ dev.sxpr() for dev in devs ]
diff -Naur xen-2.0/tools/python/xen/xend/XendClient.py
xen_creditlimit/tools/python/xen/xend/XendClient.py
--- xen-2.0/tools/python/xen/xend/XendClient.py 2005-02-04
13:38:28.000000000 +0000
+++ xen_creditlimit/tools/python/xen/xend/XendClient.py 2005-02-28
10:38:24.000000000 +0000
@@ -278,6 +278,13 @@
{ 'op' : 'maxmem_set',
'memory' : memory })
+ def xend_domain_vif_limit(self, id, vif, credit, period):
+ return self.xendPost(self.domainurl(id),
+ { 'op' : 'vif_credit_limit',
+ 'vif' : vif,
+ 'credit' : credit,
+ 'period' : period })
+
def xend_domain_vifs(self, id):
return self.xendGet(self.domainurl(id),
{ 'op' : 'vifs' })
diff -Naur xen-2.0/tools/python/xen/xend/XendDomainInfo.py
xen_creditlimit/tools/python/xen/xend/XendDomainInfo.py
--- xen-2.0/tools/python/xen/xend/XendDomainInfo.py 2005-02-04
13:38:31.000000000 +0000
+++ xen_creditlimit/tools/python/xen/xend/XendDomainInfo.py
2005-02-28 11:12:38.000000000 +0000
@@ -597,6 +597,18 @@
def get_device_recreate(self, type, index):
return self.get_device_savedinfo(type, index) or self.recreate
+ def limit_vif(self, vif, credit, period):
+ """Limit the rate of a virtual interface
+ @param vif: vif
+ @param credit: vif credit in bytes
+ @param period: vif period in uSec
+ @return: 0 on success
+ """
+
+ ctrl = xend.netif_create(self.dom, recreate=self.recreate)
+ d = ctrl.limitDevice(vif, credit, period)
+ return d
+
def add_config(self, val):
"""Add configuration data to a virtual machine.
@@ -1090,8 +1102,6 @@
vifs = vm.config_devices("vif")
vm.create_domain("plan9", kernel, ramdisk, cmdline)
return vm
-
-
def vm_dev_vif(vm, val, index, change=0):
"""Create a virtual network interface (vif).
diff -Naur xen-2.0/tools/python/xen/xend/XendDomain.py
xen_creditlimit/tools/python/xen/xend/XendDomain.py
--- xen-2.0/tools/python/xen/xend/XendDomain.py 2005-02-04
13:38:31.000000000 +0000
+++ xen_creditlimit/tools/python/xen/xend/XendDomain.py 2005-02-28
11:12:46.000000000 +0000
@@ -723,6 +723,15 @@
dominfo = self.domain_lookup(id)
return dominfo.get_device_by_index(type, idx)
+ def domain_vif_credit_limit(self, id, vif, credit, period):
+ """Limit the vif's transmission rate
+ """
+ dominfo = self.domain_lookup(id)
+ try:
+ return dominfo.limit_vif(vif, credit, period)
+ except Exception, ex:
+ raise XendError(str(ex))
+
def domain_vif_ls(self, id):
"""Get list of virtual network interface (vif) indexes for a
domain.
diff -Naur xen-2.0/tools/python/xen/xm/main.py
xen_creditlimit/tools/python/xen/xm/main.py
--- xen-2.0/tools/python/xen/xm/main.py 2005-02-04 13:38:38.000000000
+0000
+++ xen_creditlimit/tools/python/xen/xm/main.py 2005-02-27
15:45:48.000000000 +0000
@@ -717,6 +717,23 @@
xm.prog(ProgLog)
+class ProgVifCreditLimit(Prog):
+ group = 'vif'
+ name= "vif-limit"
+ info = """Limit the transmission rate of a virtual network
interface."""
+
+ def help(self, args):
+ print args[0], "DOMAIN VIF CREDIT_IN_BYTES PERIOD_IN_USECS"
+ print "\nSet the credit limit of a virtual network interface."
+
+ def main(self, args):
+ if len(args) != 5: self.err("%s: Invalid argument(s)" %
args[0])
+ dom = args[1]
+ v = map(int, args[2:5])
+ server.xend_domain_vif_limit(dom, *v)
+
+xm.prog(ProgVifCreditLimit)
+
class ProgVifList(Prog):
group = 'vif'
name = 'vif-list'
diff -Naur xen-2.0/xen/include/public/io/domain_controller.h
xen_creditlimit/xen/include/public/io/domain_controller.h
--- xen-2.0/xen/include/public/io/domain_controller.h 2005-02-04
13:38:38.000000000 +0000
+++ xen_creditlimit/xen/include/public/io/domain_controller.h
2005-02-27 16:43:38.000000000 +0000
@@ -436,6 +436,7 @@
#define CMSG_NETIF_BE_DESTROY 1 /* Destroy a net-device interface.
*/
#define CMSG_NETIF_BE_CONNECT 2 /* Connect i/f to remote driver.
*/
#define CMSG_NETIF_BE_DISCONNECT 3 /* Disconnect i/f from remote
driver. */
+#define CMSG_NETIF_BE_CREDITLIMIT 4 /* Limit i/f to a given credit
limit. */
/* Messages to domain controller. */
#define CMSG_NETIF_BE_DRIVER_STATUS 32
@@ -498,6 +499,22 @@
} PACKED netif_be_destroy_t; /* 12 bytes */
/*
+ * CMSG_NETIF_BE_CREDITLIMIT:
+ * Limit a virtual interface to "credit_bytes" bytes per "period_usec"
+ * microseconds.
+ */
+typedef struct {
+ /* IN */
+ domid_t domid; /* 0: Domain attached to new interface.
*/
+ u16 __pad0; /* 2 */
+ u32 netif_handle; /* 4: Domain-specific interface handle.
*/
+ u32 credit_bytes; /* 8: Vifs credit of bytes per period.
*/
+ u32 period_usec; /* 12: Credit replenishment period.
*/
+ /* OUT */
+ u32 status; /* 16 */
+} PACKED netif_be_creditlimit_t; /* 20 bytes */
+
+/*
* CMSG_NETIF_BE_CONNECT:
* When the driver sends a successful response then the interface is
fully
* connected. The controller will send a CONNECTED notification to the
-------------------------------------------------------
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