v / vlib / sync
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1// vtest flaky: true
2// vtest retry: 15
3
4// This test case runs concurrent 3 instances of `do_select` that
5// communicate with 6 other threads doing send and receive operations.
6// There are buffered and unbuffered channels - handled by one or two
7// concurrend threads on the other side
8
9fn do_select(ch1 chan int, ch2 chan int, chf1 chan f64, chf2 chan f64, sumch1 chan i64, sumch2 chan i64) {
10 mut sum1 := i64(0)
11 mut sum2 := i64(0)
12 f1 := 17.0
13 f2 := 7.0
14 for _ in 0 .. 20000 + chf1.cap / 3 {
15 select {
16 chf1 <- f1 {}
17 i := <-ch1 {
18 sum1 += i
19 }
20 j := <-ch2 {
21 sum2 += j
22 }
23 chf2 <- f2 {}
24 }
25 }
26 sumch1 <- sum1
27 sumch2 <- sum2
28}
29
30fn do_send_int(ch chan int, factor int) {
31 for i in 0 .. 10000 {
32 ch <- (i * factor)
33 }
34}
35
36fn do_rec_f64(ch chan f64, sumch chan f64) {
37 mut sum := 0.0
38 for _ in 0 .. 10000 {
39 sum += <-ch
40 }
41 sumch <- sum
42}
43
44fn test_select() {
45 ch1 := chan int{cap: 3}
46 ch2 := chan int{}
47 // buffer length of chf1 mus be mutiple of 3 (# select threads)
48 chf1 := chan f64{cap: 30}
49 chf2 := chan f64{}
50 chsum1 := chan i64{}
51 chsum2 := chan i64{}
52 chsumf1 := chan f64{}
53 chsumf2 := chan f64{}
54 spawn do_send_int(ch1, 3)
55 spawn do_select(ch1, ch2, chf1, chf2, chsum1, chsum2)
56 spawn do_rec_f64(chf1, chsumf1)
57 spawn do_rec_f64(chf2, chsumf2)
58 spawn do_rec_f64(chf2, chsumf2)
59 spawn do_select(ch1, ch2, chf1, chf2, chsum1, chsum2)
60 spawn do_send_int(ch2, 7)
61 spawn do_send_int(ch2, 17)
62 spawn do_select(ch1, ch2, chf1, chf2, chsum1, chsum2)
63
64 sum1 := <-chsum1 + <-chsum1 + <-chsum1
65 sum2 := <-chsum2 + <-chsum2 + <-chsum2
66 mut sumf1 := <-chsumf1
67 // empty channel buffer
68 for _ in 0 .. chf1.cap {
69 sumf1 += <-chf1
70 }
71 sumf2 := <-chsumf2 + <-chsumf2
72 // Use Gauß' formula
73 expected_sum := i64(10000) * (10000 - 1) / 2
74 assert sum1 == 3 * expected_sum
75 assert sum2 == (7 + 17) * expected_sum
76 assert sumf1 == 17.0 * f64(10000 + chf1.cap)
77 assert sumf2 == 7.0 * 20000
78}