4 ms·

It seems like this would be more compelling if accompanied by some benchmarks showing how much better the performance is than the original zlib's.

by gjm11 11y ago

moreati 11y ago
A very rough and ready, impromptu benchmark. zlib latest took 26 seconds to compress 648 MB of text, zlib-ng latest took 16 seconds. alex@martha:~/src/zlib$ export TESTFILE=../enwiki-20141106-pages-articles-multistream-index.txt alex@martha:~/src/zlib$ du -h $TESTFILE 648M /home/alex/src/enwiki-20141106-pages-articles-multistream-index.txt alex@martha:~/src/zlib$ LD_LIBRARY_PATH=./ time ./minigzip <$TESTFILE >/dev/null 23.75user 0.17system 0:26.05elapsed 91%CPU (0avgtext+0avgdata 1864maxresident)k 56472inputs+0outputs (0major+144minor)pagefaults 0swaps alex@martha:~/src/zlib$ LD_LIBRARY_PATH=./ time ./minigzip <$TESTFILE >/dev/null 24.29user 0.17system 0:26.80elapsed 91%CPU (0avgtext+0avgdata 1772maxresident)k 0inputs+0outputs (0major+141minor)pagefaults 0swaps alex@martha:~/src/zlib$ cd ../zlib-ng alex@martha:~/src/zlib-ng$ LD_LIBRARY_PATH=./ time ./minigzip <$TESTFILE >/dev/null 14.66user 0.11system 0:16.16elapsed 91%CPU (0avgtext+0avgdata 1604maxresident)k 256inputs+0outputs (0major+140minor)pagefaults 0swaps alex@martha:~/src/zlib-ng$ LD_LIBRARY_PATH=./ time ./minigzip <$TESTFILE >/dev/null 14.64user 0.12system 0:16.09elapsed 91%CPU (0avgtext+0avgdata 1840maxresident)k 0inputs+0outputs (0major+144minor)pagefaults 0swaps The machine is a MBP 11,2 with an i7-4750HQ CPU @ 2.00GHz, running Ubuntu 15.04 x64.
- nly 11y ago
  What about decompression? Are we already I/O bound? Compression is irrelevant in many cases, where you can precompress static content.
  - moreati 11y ago
    zlib latest takes 3 seconds, zlib-ng takes 13 seconds alex@martha:~/src/zlib$ du -sh $TESTFILE 197M /home/alex/src/enwiki-20141106-pages-articles-multistream-index.txt.gz alex@martha:~/src/zlib$ LD_LIBRARY_PATH=./ time ./minigzip -d <$TESTFILE >/dev/null 3.36user 0.03system 0:03.87elapsed 87%CPU (0avgtext+0avgdata 1632maxresident)k 8inputs+0outputs (0major+90minor)pagefaults 0swaps alex@martha:~/src/zlib$ LD_LIBRARY_PATH=./ time ./minigzip -d <$TESTFILE >/dev/null 3.34user 0.04system 0:03.76elapsed 90%CPU (0avgtext+0avgdata 1704maxresident)k 0inputs+0outputs (0major+91minor)pagefaults 0swaps alex@martha:~/src/zlib$ cd ../zlib-ng/ alex@martha:~/src/zlib-ng$ LD_LIBRARY_PATH=./ time ./minigzip -d <$TESTFILE >/dev/null 12.20user 0.04system 0:13.63elapsed 89%CPU (0avgtext+0avgdata 1576maxresident)k 264inputs+0outputs (1major+86minor)pagefaults 0swaps alex@martha:~/src/zlib-ng$ LD_LIBRARY_PATH=./ time ./minigzip -d <$TESTFILE >/dev/null 12.15user 0.08system 0:13.58elapsed 90%CPU (0avgtext+0avgdata 1428maxresident)k 0inputs+0outputs (0major+84minor)pagefaults 0swaps
    - gjm11 11y ago
      So the optimizations in zlib-ng enable it to decompress ... more than 4x slower than vanilla zlib? That seems worthy of some further investigation.
    - pimlottc 11y ago
      I'm curious, was your decompression test file compressed with zlib? zlib-ng? Does it make a difference?
  - Dead2 11y ago
    Unfortunately the minigzip implementation used is using a very minimal codebase to implement the functionality, among these is a problem where it will read and decompress 1 byte per call to inflate(). A patch and pull request for this has been available since yesterday at least, and I merged this today. In stock zlib this codepath is only used if you defined Z_SOLO, but in zlib-ng it is the default unless you run configure with --zlib-compat (or otherwise set the correct defines). Please retest with the updated commit, or even better with --zlib-compat if you want to get close to an apples-to-apples comparison. EDIT: PS: This goes to show that minigzip can not really be used as a reliable benchmark, since actual applications linking to the library could be using it differently (for better or worse).
jsnell 11y ago
Edit: Results with zlib-ng and a newer version of the Cloudflare changes: https://www.snellman.net/blog/archive/2015-06-05-updated-zlib-benchmarks/ https://www.snellman.net/blog/archive/2015-06-05-updated-zli... Original: Here are some benchmarks of the Intel and Cloudflare forks that this project is based on: https://www.snellman.net/blog/archive/2014-08-04-comparison-of-intel-and-cloudflare-zlib-patches.html https://www.snellman.net/blog/archive/2014-08-04-comparison-... The speedups are not insignificant. (I'll see about updating the post to include results for zlib-ng).
- Dead2 11y ago
  As I mentioned in another comment, the minigzip used is very suboptimal due to reading and decompressing only 1 byte per inflate() call. Please retest with --zlib-compat or the fix that was merged today.
  - jsnell 11y ago
    Sure thing, updated. I'm not in the habit of including compression level 6 in the results, since the application I care about defaults to 5 :) And I wanted a good spread of different compression levels in the results.
- Dead2 11y ago
  Btw, I always wondered.. Why didn't you test compression level 6, it is the default level, and used by for example stock apache/nginx settings. Also #zlib-ng on freenode if you or anyone else want to discuss.

It seems like this would be more compelling if accompanied by some benchmarks showing how much better the performance is than the original zlib's.

by gjm11 11y ago

It seems like this would be more compelling if accompanied by some benchmarks showing how much better the performance is than the original zlib's.

moreati 11y ago

A very rough and ready, impromptu benchmark. zlib latest took 26 seconds to compress 648 MB of text, zlib-ng latest took 16 seconds. alex@martha:~/src/zlib$ export TESTFILE=../enwiki-20141106-pages-articles-multistream-index.txt alex@martha:~/src/zlib$ du -h $TESTFILE 648M /home/alex/src/enwiki-20141106-pages-articles-multistream-index.txt alex@martha:~/src/zlib$ LD_LIBRARY_PATH=./ time ./minigzip <$TESTFILE >/dev/null 23.75user 0.17system 0:26.05elapsed 91%CPU (0avgtext+0avgdata 1864maxresident)k 56472inputs+0outputs (0major+144minor)pagefaults 0swaps alex@martha:~/src/zlib$ LD_LIBRARY_PATH=./ time ./minigzip <$TESTFILE >/dev/null 24.29user 0.17system 0:26.80elapsed 91%CPU (0avgtext+0avgdata 1772maxresident)k 0inputs+0outputs (0major+141minor)pagefaults 0swaps alex@martha:~/src/zlib$ cd ../zlib-ng alex@martha:~/src/zlib-ng$ LD_LIBRARY_PATH=./ time ./minigzip <$TESTFILE >/dev/null 14.66user 0.11system 0:16.16elapsed 91%CPU (0avgtext+0avgdata 1604maxresident)k 256inputs+0outputs (0major+140minor)pagefaults 0swaps alex@martha:~/src/zlib-ng$ LD_LIBRARY_PATH=./ time ./minigzip <$TESTFILE >/dev/null 14.64user 0.12system 0:16.09elapsed 91%CPU (0avgtext+0avgdata 1840maxresident)k 0inputs+0outputs (0major+144minor)pagefaults 0swaps The machine is a MBP 11,2 with an i7-4750HQ CPU @ 2.00GHz, running Ubuntu 15.04 x64.

nly 11y ago
What about decompression? Are we already I/O bound? Compression is irrelevant in many cases, where you can precompress static content.
- moreati 11y ago
  zlib latest takes 3 seconds, zlib-ng takes 13 seconds alex@martha:~/src/zlib$ du -sh $TESTFILE 197M /home/alex/src/enwiki-20141106-pages-articles-multistream-index.txt.gz alex@martha:~/src/zlib$ LD_LIBRARY_PATH=./ time ./minigzip -d <$TESTFILE >/dev/null 3.36user 0.03system 0:03.87elapsed 87%CPU (0avgtext+0avgdata 1632maxresident)k 8inputs+0outputs (0major+90minor)pagefaults 0swaps alex@martha:~/src/zlib$ LD_LIBRARY_PATH=./ time ./minigzip -d <$TESTFILE >/dev/null 3.34user 0.04system 0:03.76elapsed 90%CPU (0avgtext+0avgdata 1704maxresident)k 0inputs+0outputs (0major+91minor)pagefaults 0swaps alex@martha:~/src/zlib$ cd ../zlib-ng/ alex@martha:~/src/zlib-ng$ LD_LIBRARY_PATH=./ time ./minigzip -d <$TESTFILE >/dev/null 12.20user 0.04system 0:13.63elapsed 89%CPU (0avgtext+0avgdata 1576maxresident)k 264inputs+0outputs (1major+86minor)pagefaults 0swaps alex@martha:~/src/zlib-ng$ LD_LIBRARY_PATH=./ time ./minigzip -d <$TESTFILE >/dev/null 12.15user 0.08system 0:13.58elapsed 90%CPU (0avgtext+0avgdata 1428maxresident)k 0inputs+0outputs (0major+84minor)pagefaults 0swaps
  - gjm11 11y ago
    So the optimizations in zlib-ng enable it to decompress ... more than 4x slower than vanilla zlib? That seems worthy of some further investigation.
  - pimlottc 11y ago
    I'm curious, was your decompression test file compressed with zlib? zlib-ng? Does it make a difference?
- Dead2 11y ago
  Unfortunately the minigzip implementation used is using a very minimal codebase to implement the functionality, among these is a problem where it will read and decompress 1 byte per call to inflate(). A patch and pull request for this has been available since yesterday at least, and I merged this today. In stock zlib this codepath is only used if you defined Z_SOLO, but in zlib-ng it is the default unless you run configure with --zlib-compat (or otherwise set the correct defines). Please retest with the updated commit, or even better with --zlib-compat if you want to get close to an apples-to-apples comparison. EDIT: PS: This goes to show that minigzip can not really be used as a reliable benchmark, since actual applications linking to the library could be using it differently (for better or worse).

jsnell 11y ago

Edit: Results with zlib-ng and a newer version of the Cloudflare changes: https://www.snellman.net/blog/archive/2015-06-05-updated-zlib-benchmarks/ https://www.snellman.net/blog/archive/2015-06-05-updated-zli... Original: Here are some benchmarks of the Intel and Cloudflare forks that this project is based on: https://www.snellman.net/blog/archive/2014-08-04-comparison-of-intel-and-cloudflare-zlib-patches.html https://www.snellman.net/blog/archive/2014-08-04-comparison-... The speedups are not insignificant. (I'll see about updating the post to include results for zlib-ng).

Dead2 11y ago
As I mentioned in another comment, the minigzip used is very suboptimal due to reading and decompressing only 1 byte per inflate() call. Please retest with --zlib-compat or the fix that was merged today.
- jsnell 11y ago
  Sure thing, updated. I'm not in the habit of including compression level 6 in the results, since the application I care about defaults to 5 :) And I wanted a good spread of different compression levels in the results.
Dead2 11y ago
Btw, I always wondered.. Why didn't you test compression level 6, it is the default level, and used by for example stock apache/nginx settings. Also #zlib-ng on freenode if you or anyone else want to discuss.