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git.proxmox.com Git - mirror_ovs.git/blob - tests/test-multipath.c
2 * Copyright (c) 2010 Nicira Networks.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
19 #include "multipath.h"
32 main(int argc
, char *argv
[])
34 enum { MP_MAX_LINKS
= 63 };
35 struct nx_action_multipath mp
;
39 set_program_name(argv
[0]);
43 ovs_fatal(0, "usage: %s multipath_action", program_name
);
46 multipath_parse(&mp
, argv
[1]);
47 for (n
= 1; n
<= MP_MAX_LINKS
; n
++) {
48 enum { N_FLOWS
= 65536 };
49 double disruption
, perfect
, distribution
;
50 int histogram
[MP_MAX_LINKS
];
51 double sum_dev2
, stddev
;
56 memset(histogram
, 0, sizeof histogram
);
57 for (i
= 0; i
< N_FLOWS
; i
++) {
58 int old_link
, new_link
;
61 random_bytes(&flow
, sizeof flow
);
63 mp
.max_link
= htons(n
- 1);
64 multipath_execute(&mp
, &flow
);
65 old_link
= flow
.regs
[0];
67 mp
.max_link
= htons(n
);
68 multipath_execute(&mp
, &flow
);
69 new_link
= flow
.regs
[0];
71 assert(old_link
>= 0 && old_link
< n
);
72 assert(new_link
>= 0 && new_link
< n
+ 1);
74 histogram
[old_link
]++;
75 changed
+= old_link
!= new_link
;
79 for (i
= 0; i
< n
; i
++) {
80 double mean
= (double) N_FLOWS
/ n
;
81 double deviation
= histogram
[i
] - mean
;
83 sum_dev2
+= deviation
* deviation
;
85 stddev
= sqrt(sum_dev2
/ n
);
87 disruption
= (double) changed
/ N_FLOWS
;
88 perfect
= 1.0 / (n
+ 1);
89 distribution
= stddev
/ ((double) N_FLOWS
/ n
);
90 printf("%2d -> %2d: disruption=%.2f (perfect=%.2f); "
91 "stddev/expected=%.4f\n",
92 n
, n
+ 1, disruption
, perfect
, distribution
);
94 switch (ntohs(mp
.algorithm
)) {
95 case NX_MP_ALG_MODULO_N
:
96 if (disruption
< (n
< 2 ? .25 : .5)) {
97 fprintf(stderr
, "%d -> %d: disruption=%.2f < .5\n",
98 n
, n
+ 1, disruption
);
103 case NX_MP_ALG_HASH_THRESHOLD
:
104 if (disruption
< .48 || disruption
> .52) {
105 fprintf(stderr
, "%d -> %d: disruption=%.2f not approximately "
106 ".5\n", n
, n
+ 1, disruption
);
111 case NX_MP_ALG_ITER_HASH
:
112 if (!(n
& (n
- 1))) {
117 if (fabs(disruption
- perfect
) >= .01) {
118 fprintf(stderr
, "%d -> %d: disruption=%.5f differs from "
119 "perfect=%.5f by more than .01\n",
120 n
, n
+ 1, disruption
, perfect
);