[Issue 18388] New: std.experimental.logger slow performance

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=18388

          Issue ID: 18388
           Summary: std.experimental.logger slow performance
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P1
         Component: phobos
          Assignee: nobody at puremagic.com
          Reporter: aruncxy at gmail.com

std.experimental.logger is very slow when compared to some implementation in
C++ (spdlog)

>From my initial observations, the max CPU usage per thread doesn't exceed 30%
on average.

07-02-2018 00:09:00 vaalaham ~/code/cpp/spdlog/bench 
$ make >/dev/null 2>&1 && time ./spdlog-bench-mt 8

real    0m0.562s
user    0m1.480s
sys     0m1.620s
07-02-2018 00:09:05 vaalaham ~/code/cpp/spdlog/bench
$
07-02-2018 00:09:26 vaalaham ~/code/d/std-log-benchmark
$ time ./std-log-benchmark 8 1000000

real    0m5.617s
user    0m4.048s
sys     0m3.674s
07-02-2018 00:09:34 vaalaham ~/code/d/std-log-benchmark
$

import core.atomic;
import core.thread;

import std.parallelism;
import std.experimental.logger;
import std.stdio;
import std.conv : to;

shared int msgCounter = 0;
shared int maxCount = 1_000_000;
__gshared FileLogger _logger;

void main(string[] args)
{
    if (args.length != 3)
    {
        writefln("Usage: %s <thread-count> <loop-count>", args[0]);
        return;
    }

    _logger = new FileLogger("/dev/null", LogLevel.trace);
    const threadCount = to!int(args[1]);
    maxCount = to!int(args[2]) - threadCount;
    auto pool = new TaskPool(threadCount);
    foreach (tid; 0 .. threadCount)
        pool.put(task!logMe(tid + 1));
    pool.finish;
}

void logMe(const int tid)
{
    while (true)
    {
        _logger.tracef("From T-%s log message #%s: This is some text for your
pleasure", tid, atomicOp!"+="(msgCounter, 1));
        if (atomicLoad(msgCounter) > maxCount)
            break;
    }
}

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