Date:   Tue, 19 Dec 2017 15:33:46 +0900
From:   Chris Mi <chrism@...lanox.com>
To:     netdev@...r.kernel.org
Cc:     gerlitz.or@...il.com
Subject: [patch iproute2] tc: add -bs option for batch mode

Currently in tc batch mode, only one command is read from the batch
file and sent to kernel to process. With this patch, we can accumulate
several commands before sending to kernel. The batch size is specified
using option -bs or -batchsize.

To accumulate the commands in tc, we allocate an array of struct iovec.
If batchsize is bigger than 1 and we haven't accumulated enough
commands, rtnl_talk() will return without actually sending the message.
One exception is that there is no more command in the batch file.

But please note that kernel still processes the requests one by one.
To process the requests in parallel in kernel is another effort.
The time we're saving in this patch is the user mode and kernel mode
context switch. So this patch works on top of the current kernel.

Using the following script in kernel, we can generate 1,000,000 rules.
	tools/testing/selftests/tc-testing/tdc_batch.py

Without this patch, 'tc -b $file' exection time is:

real    0m14.916s
user    0m6.808s
sys     0m8.046s

With this patch, 'tc -b $file -bs 10' exection time is:

real    0m12.286s
user    0m5.903s
sys     0m6.312s

The insertion rate is improved more than 10%.

Signed-off-by: Chris Mi <chrism@...lanox.com>
---
 include/libnetlink.h | 27 ++++++++++++++++
 include/utils.h      |  8 +++++
 lib/libnetlink.c     | 30 +++++++++++++-----
 lib/utils.c          | 20 ++++++++++++
 man/man8/tc.8        |  5 +++
 tc/m_action.c        | 63 ++++++++++++++++++++++++++++---------
 tc/tc.c              | 27 ++++++++++++++--
 tc/tc_common.h       |  3 ++
 tc/tc_filter.c       | 89 ++++++++++++++++++++++++++++++++++++----------------
 9 files changed, 221 insertions(+), 51 deletions(-)

diff --git a/include/libnetlink.h b/include/libnetlink.h
index a4d83b9e..07e88c94 100644
--- a/include/libnetlink.h
+++ b/include/libnetlink.h
@@ -13,6 +13,8 @@
 #include <linux/netconf.h>
 #include <arpa/inet.h>
 
+#define MSG_IOV_MAX 256
+
 struct rtnl_handle {
 	int			fd;
 	struct sockaddr_nl	local;
@@ -93,6 +95,31 @@ int rtnl_dump_filter_nc(struct rtnl_handle *rth,
 			void *arg, __u16 nc_flags);
 #define rtnl_dump_filter(rth, filter, arg) \
 	rtnl_dump_filter_nc(rth, filter, arg, 0)
+
+extern int msg_iov_index;
+static inline int get_msg_iov_index(void)
+{
+	return msg_iov_index;
+}
+static inline void set_msg_iov_index(int index)
+{
+	msg_iov_index = index;
+}
+static inline void incr_msg_iov_index(void)
+{
+	++msg_iov_index;
+}
+
+extern int batch_size;
+static inline int get_batch_size(void)
+{
+	return batch_size;
+}
+static inline void set_batch_size(int size)
+{
+	batch_size = size;
+}
+
 int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 	      struct nlmsghdr **answer)
 	__attribute__((warn_unused_result));
diff --git a/include/utils.h b/include/utils.h
index d3895d56..66cb4747 100644
--- a/include/utils.h
+++ b/include/utils.h
@@ -235,6 +235,14 @@ void print_nlmsg_timestamp(FILE *fp, const struct nlmsghdr *n);
 
 extern int cmdlineno;
 ssize_t getcmdline(char **line, size_t *len, FILE *in);
+
+extern int cmdlinetotal;
+static inline int getcmdlinetotal(void)
+{
+	return cmdlinetotal;
+}
+void setcmdlinetotal(const char *name);
+
 int makeargs(char *line, char *argv[], int maxargs);
 int inet_get_addr(const char *src, __u32 *dst, struct in6_addr *dst6);
 
diff --git a/lib/libnetlink.c b/lib/libnetlink.c
index 00e6ce0c..f9be1c6d 100644
--- a/lib/libnetlink.c
+++ b/lib/libnetlink.c
@@ -24,6 +24,7 @@
 #include <sys/uio.h>
 
 #include "libnetlink.h"
+#include "utils.h"
 
 #ifndef SOL_NETLINK
 #define SOL_NETLINK 270
@@ -581,6 +582,10 @@ static void rtnl_talk_error(struct nlmsghdr *h, struct nlmsgerr *err,
 		strerror(-err->error));
 }
 
+static struct iovec msg_iov[MSG_IOV_MAX];
+int msg_iov_index;
+int batch_size = 1;
+
 static int __rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 		       struct nlmsghdr **answer,
 		       bool show_rtnl_err, nl_ext_ack_fn_t errfn)
@@ -589,23 +594,34 @@ static int __rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 	unsigned int seq;
 	struct nlmsghdr *h;
 	struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
-	struct iovec iov = {
-		.iov_base = n,
-		.iov_len = n->nlmsg_len
-	};
+	struct iovec *iov = &msg_iov[get_msg_iov_index()];
+	int index;
+	char *buf;
+
+	iov->iov_base = n;
+	iov->iov_len = n->nlmsg_len;
+
+	incr_msg_iov_index();
 	struct msghdr msg = {
 		.msg_name = &nladdr,
 		.msg_namelen = sizeof(nladdr),
-		.msg_iov = &iov,
-		.msg_iovlen = 1,
+		.msg_iov = msg_iov,
+		.msg_iovlen = get_msg_iov_index(),
 	};
-	char *buf;
 
 	n->nlmsg_seq = seq = ++rtnl->seq;
 
 	if (answer == NULL)
 		n->nlmsg_flags |= NLM_F_ACK;
 
+	index = get_msg_iov_index() % get_batch_size();
+	if (index != 0 && get_batch_size() > 1 &&
+	    cmdlineno != getcmdlinetotal() &&
+	    (n->nlmsg_type == RTM_NEWTFILTER ||
+	    n->nlmsg_type == RTM_NEWACTION))
+		return 3;
+	set_msg_iov_index(index);
+
 	status = sendmsg(rtnl->fd, &msg, 0);
 	if (status < 0) {
 		perror("Cannot talk to rtnetlink");
diff --git a/lib/utils.c b/lib/utils.c
index 7ced8c06..53ca389f 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -1202,6 +1202,26 @@ ssize_t getcmdline(char **linep, size_t *lenp, FILE *in)
 	return cc;
 }
 
+int cmdlinetotal;
+
+void setcmdlinetotal(const char *name)
+{
+	char *line = NULL;
+	size_t len = 0;
+
+	if (name && strcmp(name, "-") != 0) {
+		if (freopen(name, "r", stdin) == NULL) {
+			fprintf(stderr, "Cannot open file \"%s\" for reading: %s\n",
+				name, strerror(errno));
+			return;
+		}
+	}
+
+	cmdlinetotal = 0;
+	while (getcmdline(&line, &len, stdin) != -1)
+		cmdlinetotal++;
+}
+
 /* split command line into argument vector */
 int makeargs(char *line, char *argv[], int maxargs)
 {
diff --git a/man/man8/tc.8 b/man/man8/tc.8
index ff071b33..de137e16 100644
--- a/man/man8/tc.8
+++ b/man/man8/tc.8
@@ -601,6 +601,11 @@ must exist already.
 read commands from provided file or standard input and invoke them.
 First failure will cause termination of tc.
 
+.TP
+.BR "\-bs", " \-bs size", " \-batchsize", " \-batchsize size"
+How many commands are accumulated before sending to kernel.
+By default, it is 1. It only takes effect in batch mode.
+
 .TP
 .BR "\-force"
 don't terminate tc on errors in batch mode.
diff --git a/tc/m_action.c b/tc/m_action.c
index 13f942bf..574b78ca 100644
--- a/tc/m_action.c
+++ b/tc/m_action.c
@@ -23,6 +23,7 @@
 #include <arpa/inet.h>
 #include <string.h>
 #include <dlfcn.h>
+#include <errno.h>
 
 #include "utils.h"
 #include "tc_common.h"
@@ -546,33 +547,65 @@ bad_val:
 	return ret;
 }
 
+typedef struct {
+	struct nlmsghdr		n;
+	struct tcamsg		t;
+	char			buf[MAX_MSG];
+} tc_action_req;
+
+static tc_action_req *action_reqs;
+
+void free_action_reqs(void)
+{
+	if (action_reqs)
+		free(action_reqs);
+}
+
+static tc_action_req *get_action_req(void)
+{
+	tc_action_req *req;
+
+	if (action_reqs == NULL) {
+		action_reqs = malloc(get_batch_size() * sizeof (tc_action_req));
+		if (action_reqs == NULL)
+			return NULL;
+	}
+	req = &action_reqs[get_msg_iov_index()];
+	memset(req, 0, sizeof (*req));
+
+	return req;
+}
+
 static int tc_action_modify(int cmd, unsigned int flags,
 			    int *argc_p, char ***argv_p)
 {
 	int argc = *argc_p;
 	char **argv = *argv_p;
 	int ret = 0;
-	struct {
-		struct nlmsghdr         n;
-		struct tcamsg           t;
-		char                    buf[MAX_MSG];
-	} req = {
-		.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcamsg)),
-		.n.nlmsg_flags = NLM_F_REQUEST | flags,
-		.n.nlmsg_type = cmd,
-		.t.tca_family = AF_UNSPEC,
-	};
-	struct rtattr *tail = NLMSG_TAIL(&req.n);
+	tc_action_req *req;
+
+	req = get_action_req();
+	if (req == NULL) {
+		fprintf(stderr, "get_action_req error: not enough buffer\n");
+		return -ENOMEM;
+	}
+
+	req->n.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcamsg));
+	req->n.nlmsg_flags = NLM_F_REQUEST | flags;
+	req->n.nlmsg_type = cmd;
+	req->t.tca_family = AF_UNSPEC;
+	struct rtattr *tail = NLMSG_TAIL(&req->n);
 
 	argc -= 1;
 	argv += 1;
-	if (parse_action(&argc, &argv, TCA_ACT_TAB, &req.n)) {
+	if (parse_action(&argc, &argv, TCA_ACT_TAB, &req->n)) {
 		fprintf(stderr, "Illegal \"action\"\n");
 		return -1;
 	}
-	tail->rta_len = (void *) NLMSG_TAIL(&req.n) - (void *) tail;
+	tail->rta_len = (void *) NLMSG_TAIL(&req->n) - (void *) tail;
 
-	if (rtnl_talk(&rth, &req.n, NULL) < 0) {
+	ret = rtnl_talk(&rth, &req->n, NULL);
+	if (ret < 0) {
 		fprintf(stderr, "We have an error talking to the kernel\n");
 		ret = -1;
 	}
@@ -739,5 +772,5 @@ int do_action(int argc, char **argv)
 			return -1;
 	}
 
-	return 0;
+	return ret;
 }
diff --git a/tc/tc.c b/tc/tc.c
index ad9f07e9..9c8e828b 100644
--- a/tc/tc.c
+++ b/tc/tc.c
@@ -189,7 +189,7 @@ static void usage(void)
 	fprintf(stderr, "Usage: tc [ OPTIONS ] OBJECT { COMMAND | help }\n"
 			"       tc [-force] -batch filename\n"
 			"where  OBJECT := { qdisc | class | filter | action | monitor | exec }\n"
-	                "       OPTIONS := { -s[tatistics] | -d[etails] | -r[aw] | -p[retty] | -b[atch] [filename] | -n[etns] name |\n"
+	                "       OPTIONS := { -s[tatistics] | -d[etails] | -r[aw] | -p[retty] | -b[atch] [filename] | -bs | -batchsize [size] | -n[etns] name |\n"
 			"                    -nm | -nam[es] | { -cf | -conf } path } | -j[son]\n");
 }
 
@@ -223,6 +223,9 @@ static int batch(const char *name)
 	size_t len = 0;
 	int ret = 0;
 
+	if (get_batch_size() > 1)
+		setcmdlinetotal(name);
+
 	batch_mode = 1;
 	if (name && strcmp(name, "-") != 0) {
 		if (freopen(name, "r", stdin) == NULL) {
@@ -248,15 +251,22 @@ static int batch(const char *name)
 		if (largc == 0)
 			continue;	/* blank line */
 
-		if (do_cmd(largc, largv)) {
+		ret = do_cmd(largc, largv);
+		if (ret != 0 && ret != 3) {
 			fprintf(stderr, "Command failed %s:%d\n", name, cmdlineno);
 			ret = 1;
 			if (!force)
 				break;
 		}
 	}
+	if (ret == 3)
+		fprintf(stderr,
+			"Command is not sent to kernel due to internal error %s:%d\n",
+			name, cmdlineno);
 	if (line)
 		free(line);
+	free_filter_reqs();
+	free_action_reqs();
 
 	rtnl_close(&rth);
 	return ret;
@@ -267,6 +277,7 @@ int main(int argc, char **argv)
 {
 	int ret;
 	char *batch_file = NULL;
+	int size;
 
 	while (argc > 1) {
 		if (argv[1][0] != '-')
@@ -297,6 +308,16 @@ int main(int argc, char **argv)
 			if (argc <= 1)
 				usage();
 			batch_file = argv[1];
+		} else if (matches(argv[1], "-batchsize") == 0 ||
+				matches(argv[1], "-bs") == 0) {
+			argc--;	argv++;
+			if (argc <= 1)
+				usage();
+			size = atoi(argv[1]);
+			if (size > MSG_IOV_MAX)
+				set_batch_size(MSG_IOV_MAX);
+			else
+				set_batch_size(size);
 		} else if (matches(argv[1], "-netns") == 0) {
 			NEXT_ARG();
 			if (netns_switch(argv[1]))
@@ -342,6 +363,8 @@ int main(int argc, char **argv)
 	}
 
 	ret = do_cmd(argc-1, argv+1);
+	free_filter_reqs();
+	free_action_reqs();
 Exit:
 	rtnl_close(&rth);
 
diff --git a/tc/tc_common.h b/tc/tc_common.h
index 264fbdac..fde8db1b 100644
--- a/tc/tc_common.h
+++ b/tc/tc_common.h
@@ -24,5 +24,8 @@ struct tc_sizespec;
 extern int parse_size_table(int *p_argc, char ***p_argv, struct tc_sizespec *s);
 extern int check_size_table_opts(struct tc_sizespec *s);
 
+extern void free_filter_reqs(void);
+extern void free_action_reqs(void);
+
 extern int show_graph;
 extern bool use_names;
diff --git a/tc/tc_filter.c b/tc/tc_filter.c
index 545cc3a1..dc53c128 100644
--- a/tc/tc_filter.c
+++ b/tc/tc_filter.c
@@ -19,6 +19,7 @@
 #include <arpa/inet.h>
 #include <string.h>
 #include <linux/if_ether.h>
+#include <errno.h>
 
 #include "rt_names.h"
 #include "utils.h"
@@ -42,18 +43,51 @@ static void usage(void)
 		"OPTIONS := ... try tc filter add <desired FILTER_KIND> help\n");
 }
 
+typedef struct {
+	struct nlmsghdr		n;
+	struct tcmsg		t;
+	char			buf[MAX_MSG];
+} tc_filter_req;
+
+static tc_filter_req *filter_reqs;
+
+void free_filter_reqs(void)
+{
+	if (filter_reqs)
+		free(filter_reqs);
+}
+
+static tc_filter_req *get_filter_req(void)
+{
+	tc_filter_req *req;
+
+	if (filter_reqs == NULL) {
+		filter_reqs = malloc(get_batch_size() * sizeof (tc_filter_req));
+		if (filter_reqs == NULL)
+			return NULL;
+	}
+	req = &filter_reqs[get_msg_iov_index()];
+	memset(req, 0, sizeof (*req));
+
+	return req;
+}
+
 static int tc_filter_modify(int cmd, unsigned int flags, int argc, char **argv)
 {
-	struct {
-		struct nlmsghdr	n;
-		struct tcmsg		t;
-		char			buf[MAX_MSG];
-	} req = {
-		.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
-		.n.nlmsg_flags = NLM_F_REQUEST | flags,
-		.n.nlmsg_type = cmd,
-		.t.tcm_family = AF_UNSPEC,
-	};
+	tc_filter_req *req;
+	int ret;
+
+	req = get_filter_req();
+	if (req == NULL) {
+		fprintf(stderr, "get_filter_req error: not enough buffer\n");
+		return -ENOMEM;
+	}
+
+	req->n.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg));
+	req->n.nlmsg_flags = NLM_F_REQUEST | flags;
+	req->n.nlmsg_type = cmd;
+	req->t.tcm_family = AF_UNSPEC;
+
 	struct filter_util *q = NULL;
 	__u32 prio = 0;
 	__u32 protocol = 0;
@@ -75,37 +109,37 @@ static int tc_filter_modify(int cmd, unsigned int flags, int argc, char **argv)
 				duparg("dev", *argv);
 			strncpy(d, *argv, sizeof(d)-1);
 		} else if (strcmp(*argv, "root") == 0) {
-			if (req.t.tcm_parent) {
+			if (req->t.tcm_parent) {
 				fprintf(stderr,
 					"Error: \"root\" is duplicate parent ID\n");
 				return -1;
 			}
-			req.t.tcm_parent = TC_H_ROOT;
+			req->t.tcm_parent = TC_H_ROOT;
 		} else if (strcmp(*argv, "ingress") == 0) {
-			if (req.t.tcm_parent) {
+			if (req->t.tcm_parent) {
 				fprintf(stderr,
 					"Error: \"ingress\" is duplicate parent ID\n");
 				return -1;
 			}
-			req.t.tcm_parent = TC_H_MAKE(TC_H_CLSACT,
+			req->t.tcm_parent = TC_H_MAKE(TC_H_CLSACT,
 						     TC_H_MIN_INGRESS);
 		} else if (strcmp(*argv, "egress") == 0) {
-			if (req.t.tcm_parent) {
+			if (req->t.tcm_parent) {
 				fprintf(stderr,
 					"Error: \"egress\" is duplicate parent ID\n");
 				return -1;
 			}
-			req.t.tcm_parent = TC_H_MAKE(TC_H_CLSACT,
+			req->t.tcm_parent = TC_H_MAKE(TC_H_CLSACT,
 						     TC_H_MIN_EGRESS);
 		} else if (strcmp(*argv, "parent") == 0) {
 			__u32 handle;
 
 			NEXT_ARG();
-			if (req.t.tcm_parent)
+			if (req->t.tcm_parent)
 				duparg("parent", *argv);
 			if (get_tc_classid(&handle, *argv))
 				invarg("Invalid parent ID", *argv);
-			req.t.tcm_parent = handle;
+			req->t.tcm_parent = handle;
 		} else if (strcmp(*argv, "handle") == 0) {
 			NEXT_ARG();
 			if (fhandle)
@@ -152,26 +186,26 @@ static int tc_filter_modify(int cmd, unsigned int flags, int argc, char **argv)
 		argc--; argv++;
 	}
 
-	req.t.tcm_info = TC_H_MAKE(prio<<16, protocol);
+	req->t.tcm_info = TC_H_MAKE(prio<<16, protocol);
 
 	if (chain_index_set)
-		addattr32(&req.n, sizeof(req), TCA_CHAIN, chain_index);
+		addattr32(&req->n, sizeof(*req), TCA_CHAIN, chain_index);
 
 	if (k[0])
-		addattr_l(&req.n, sizeof(req), TCA_KIND, k, strlen(k)+1);
+		addattr_l(&req->n, sizeof(*req), TCA_KIND, k, strlen(k)+1);
 
 	if (d[0])  {
 		ll_init_map(&rth);
 
-		req.t.tcm_ifindex = ll_name_to_index(d);
-		if (req.t.tcm_ifindex == 0) {
+		req->t.tcm_ifindex = ll_name_to_index(d);
+		if (req->t.tcm_ifindex == 0) {
 			fprintf(stderr, "Cannot find device \"%s\"\n", d);
 			return 1;
 		}
 	}
 
 	if (q) {
-		if (q->parse_fopt(q, fhandle, argc, argv, &req.n))
+		if (q->parse_fopt(q, fhandle, argc, argv, &req->n))
 			return 1;
 	} else {
 		if (fhandle) {
@@ -190,14 +224,15 @@ static int tc_filter_modify(int cmd, unsigned int flags, int argc, char **argv)
 	}
 
 	if (est.ewma_log)
-		addattr_l(&req.n, sizeof(req), TCA_RATE, &est, sizeof(est));
+		addattr_l(&req->n, sizeof(*req), TCA_RATE, &est, sizeof(est));
 
-	if (rtnl_talk(&rth, &req.n, NULL) < 0) {
+	ret = rtnl_talk(&rth, &req->n, NULL);
+	if (ret < 0) {
 		fprintf(stderr, "We have an error talking to the kernel\n");
 		return 2;
 	}
 
-	return 0;
+	return ret;
 }
 
 static __u32 filter_parent;
-- 
2.14.3

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