Performance Issue?

[JanSlabon]

We're evaluating Brotli compression for PDF files, which will land in the near future in the PDF specification (see here for more details).

While doing some tests on our test environments, we noticed that Brotli is (sometimes extremely) slow compared to e.g. gzcompress().

We used following test script:

$string = \str_repeat('AAAAAAABBBBBBCCCCCC', 10000);
$iterations = 100;

$start = \microtime(true);
for ($i = 0; $i < $iterations; $i++) {
    \gzcompress($string);
}
$end = \microtime(true);
echo "Flate: " . ($end - $start) . "\n";

$start = \microtime(true);
for ($i = 0; $i < $iterations; $i++) {
    \brotli_compress($string);
}
$end = \microtime(true);
echo "Brotli: " . ($end - $start) . "\n";

On Windwos this script outputs:

On a simple Docker setup (Linux) it's not that extrem but also a noticable difference:

We also tried a similar script with "official" test-data (enwik8.zip), which results in:

Is this the normal behavior?

[pavetheway91]

Brotli wasn't meant compete in compression speed. It was designed to compress mostly static web content such as javascript and css files well and to be relatively quick to uncompress compared to many other compression algos with similar compression ratios.

[JanSlabon]

Thanks! We also recognized that the time of decompression is absolutely fine.

I just wanted to know if there may be an issue with the PHP extension or if this is the normal behavior.