fritzb / memlog

Thread-safe in memory async logging

memlog

High performance thread-safe in-memory logging with lockless ring buffer data structure. The library is efficiently fast and completely non-blocking (true non-blocking as no system call are used when producing the log). The in-memory buffer can be persisted to a log file asynchronously.

Example:

#include "log.h"

int main() {
    auto log = std::make_shared<Log>();
    log->info("Hello world %d!\n", 1000L);
    log->dump();
}

dump() call will spill the logging buffer into Standard Output (stdout):

[2019 Mar  4 17:36:16.442382600:0:I:main:6] Hello world 1000!

When configured with asynchronously log-to-file, logging buffer will be written to File output in the background:

cat rxtrace.txt
[2019 Mar  4 17:36:16.442382600:0:I:main:6] Hello world 1000!

benchmark

Memlog is 2x faster than calling plain sprintf library. Memlog stores all the log in the memory for later retreival and optionaly, the buffer can be spill to disk asynchronously. Memlog is also thread safe, and can be called by multiple threads sharing the log buffer.

Memlog is useful for debugging hard to find performance intensive bugs, as logging overhead is minimum and there is no system call involved.

MEMLOG
log->info("Hello world %d!\n", i)
memlog: 10M logs/sec on Xeon servers
memlog: 2M logs/sec on Macbook Air

SPRINTF:
sprintf(buffer, "Hello world %d!\n", i)
sprintf: 5M sprintf/sec on Xeon servers

void performance_test1(shared_ptr<Log> log) {
    chrono::high_resolution_clock::time_point t1 = chrono::high_resolution_clock::now();
    for (auto i = 0; i < 1000000; i++) {
        log->info("Hello world %d!\n", i);
    }
    chrono::high_resolution_clock::time_point t2 = chrono::high_resolution_clock::now();

    auto duration = chrono::duration_cast<chrono::microseconds>(t2 - t1).count();
    cout << "1 millions write in " << duration << " microseconds" << endl;
}


./memlogTest
[2019 Mar  5 03:12:14.760732000:0:I:main:20] Hello world 1000!
[2019 Mar  5 03:12:14.760766000:1:I:main:21] Hello world 1001!
[2019 Mar  5 03:12:14.760766000:2:I:main:22] Hello world 1002!
1 millions write in 253829 microseconds

Process finished with exit code 0