4 ms·
That appears to be systemd being slow. $ dd if=/dev/urandom of=test bs=1G count=1 iflag=fullblock $ gzip -k test $ zcat test.gz | pv -a >/dev/null [ 22
by yakubin 4y ago
That appears to be systemd being slow.
$ dd if=/dev/urandom of=test bs=1G count=1 iflag=fullblock
$ gzip -k test
$ zcat test.gz | pv -a >/dev/null
[ 228MiB/s]
$ sudo journalctl -r | pv -a >/dev/null
[13.1MiB/s]
UPDATE: Gzip with more real-world data[1]:
$ gzip -k adventures-of-huckleberry-finn.txt
$ zcat adventures-of-huckleberry-finn.txt.gz | pv -a >/dev/null
[ 151MiB/s]
[1]: <https://gutenberg.org/files/76/76-0.txt https://gutenberg.org/files/76/76-0.txt>
- klauspost 4y agoBy "compressing" random data you are bypassing gzip, since it will just store your data as uncompressed blocks, making "decompression" a memcopy. With real data, deflate maxes out somewhere around there either way, but that is a bit coincidental. With modern CPUs getting increasingly smaller IPC improvements this will likely be pretty much the max decompression speed we can expect from gzip going forward.
- yakubin 4y agoIt actually made the file bigger (1.1G from 1.0G) :) I was getting the same numbers with text data I have scattered on my disk, but those were small, so I decided to generate a bigger file. But, yes, I agree a more robust benchmark would use a Mark Twain novel e.g.