sync: add vlib/sync/bench/many_writers_and_receivers_on_1_channel.v (run with --help)

vlib/sync/bench/many_writers_and_receivers_on_1_channel.v

@@ -0,0 +1,150 @@
+import os
+import os.cmdline
+import time
+import sync
+
+// Usage:
+// many_writers_and_receivers_on_1_channel [-readers 1] [-writers 4] [-chan_cap 100] [-iterations 25000] > results.csv
+//
+// You can then open results.csv in Excel/Calc and for example plot the first vs the second column.
+enum EventKind {
+	push
+	pop
+}
+
+struct Event {
+	is_set  bool
+	id      int
+	gtime   u64 // nanoseconds
+	i       int
+	kind    EventKind
+	elapsed i64 // nanoseconds, elapsed after the previous event of the same kind
+}
+
+struct Context {
+mut:
+	n_iters   int
+	n_readers int
+	n_writers int
+	//
+	pops_wg   &sync.WaitGroup
+	pops      []Event
+	//
+	pushes_wg &sync.WaitGroup
+	pushes    []Event
+}
+
+fn do_rec(ch chan int, id int, mut ctx Context) {
+	eprintln('start of  do_rec id: $id')
+	mut timer_sw_x := time.new_stopwatch({})
+	mut tmp := int(0)
+	mut i := int(0)
+	// NB: a single receiver thread can get slightly more
+	// than its fair share of sends, that is why
+	// the receiver's Event array is much larger,
+	// enough so a single receiver can potentially process all
+	// writers pushes, and it is partitioned over all of
+	// id, ctx.n_writers and n_iters:
+	n_iters := ctx.n_iters
+	base := id * n_iters * ctx.n_writers
+	for {
+		for ch.try_pop(tmp) == .success {
+			ctx.pops[base + i] = Event{
+				is_set: true
+				id: id
+				gtime: time.sys_mono_now()
+				i: i
+				kind: .pop
+				elapsed: timer_sw_x.elapsed().nanoseconds()
+			}
+			timer_sw_x.restart()
+			i++
+			if tmp == 1 {
+				ctx.pops_wg.done()
+				return
+			}
+		}
+	}
+}
+
+fn do_send(ch chan int, id int, mut ctx Context) {
+	eprintln('start of do_send id: $id')
+	mut timer_sw_x := time.new_stopwatch({})
+	n_iters := ctx.n_iters
+	base := n_iters * id // sender events can not overlap
+	for i := 0; i < n_iters; i++ {
+		idx := base + i
+		ctx.pushes[idx] = Event{
+			is_set: true
+			id: id
+			gtime: time.sys_mono_now()
+			i: i
+			kind: .push
+			elapsed: timer_sw_x.elapsed().nanoseconds()
+		}
+		timer_sw_x.restart()
+		tmp := int(0)
+		ch <- tmp
+	}
+	ctx.pushes_wg.done()
+}
+
+fn main() {
+	//
+	args := os.args[1..]
+	if '-h' in args || '--help' in args {
+		eprintln('Usage:\n many_writers_and_receivers_on_1_channel [-readers 1] [-writers 4] [-chan_cap 100] [-iterations 25000]')
+		exit(0)
+	}
+	n_iters := cmdline.option(args, '-iterations', '25000').int()
+	n_readers := cmdline.option(args, '-readers', '1').int()
+	n_writers := cmdline.option(args, '-writers', '4').int()
+	chan_cap := cmdline.option(args, '-chan_cap', '100').int()
+	eprintln('> n_iters, $n_iters, n_writers, $n_writers, n_readers, $n_readers, chan_cap, $chan_cap')
+	//
+	ch := chan int{cap: chan_cap}
+	max_number_of_pushes := n_writers * (n_iters + 2)
+	max_number_of_pops := max_number_of_pushes * n_readers
+	eprintln('> max_number_of_pushes, $max_number_of_pushes, max_number_of_pops (per receiver), $max_number_of_pops')
+	mut ctx := &Context{
+		n_iters: n_iters
+		n_readers: n_readers
+		n_writers: n_writers
+		pushes_wg: sync.new_waitgroup()
+		pops_wg: sync.new_waitgroup()
+		pushes: []Event{len: max_number_of_pushes}
+		pops: []Event{len: max_number_of_pops}
+	}
+	ctx.pops_wg.add(n_readers)
+	for i := 0; i < n_readers; i++ {
+		go do_rec(ch, i, mut ctx)
+	}
+	ctx.pushes_wg.add(n_writers)
+	for i := 0; i < n_writers; i++ {
+		go do_send(ch, i, mut ctx)
+	}
+	ctx.pushes_wg.wait()
+	eprintln('>> all pushes done')
+	for i := 0; i < n_readers; i++ {
+		ch <- 1
+	}
+	ctx.pops_wg.wait()
+	eprintln('>> all pops done')
+	mut all_events := []Event{}
+	all_events << ctx.pops
+	all_events << ctx.pushes
+	all_events.sort(a.elapsed < b.elapsed)
+	mut i := 0
+	for e in all_events {
+		if !e.is_set {
+			continue
+		}
+		i++
+		if e.kind == .pop {
+			println('${i:8} , ${e.elapsed:10}, ns ,  do_rec id:, ${e.id:3} , i=, ${e.i:5} , ${e.gtime:20}')
+		}
+		if e.kind == .push {
+			println('${i:8} , ${e.elapsed:10}, ns , do_send id:, ${e.id:3} , i=, ${e.i:5} , ${e.gtime:20}')
+		}
+	}
+}