SparkFS meets multi-core?
Julie Stamp (8365) 474 posts |
I was wondering if anyone have thoughts on passing SparkFS work off to From what I read, the Zip algorithm cannot be done in parallel, but maybe some |
David J. Ruck (33) 1635 posts |
I don’t know of any parallel zip programs, but gzip has pigz on Linux which I use to speed up compression (and decompression) when backing up raspberry Pi disc images. SparkFS could certainly make use of multi-core as it has to build the zip file in RAM (or very much more slowly to disc if it is too big) before writing the modified file back to where it came from, and it is optimised to only write the central directory a few seconds after activity has finished to avoid repeating the operation multiple as times as files being are added by filer action. Offloading the creation and compression tasks to a different core(s), would allow other processes to continue until the file is ready to be written out when activity has stopped. However, I suspect it a large amount of work, and the speed up would only be noticed when dealing with huge archives. Making sure the RAM buffer is configured large enough is far more important. |
Stuart Swales (8827) 1357 posts |
“The app’s finished writing the ZIP, I can turn off now…” |
David J. Ruck (33) 1635 posts |
We get that now, if you write files to a zip and immediately move it or email it, it will be corrupted as the central directory hasn’t been written. That is repairable though. The solution is far SparkFS to hold up the shutdown until it has flushed it’s buffers. |
Steve Pampling (1551) 8170 posts |
Close to 30 years of dealing with the average user (PC’s) indicates that there is a near certainty that numerous users will simply hit the power button. |
David J. Ruck (33) 1635 posts |
Can’t do anything about stupid. Every general purpose OS out there has write back disk caching, so pulling the plug can lose data. Plus it’s not like you can’t break Filecore that way even without caching. |
Clive Semmens (2335) 3276 posts |
And even unstupid can’t do anything about power cuts. Uninterruptible Power Supplies? Ask my friends at CUP…mains power, while not 100% reliable, has proved a bit less unreliable than even rather expensive UPSs, which have twice managed to bugger things up when there wasn’t even a mains failure. |
David Pilling (8394) 96 posts |
Google: parallel deflation algorithm zip ArjavNaik/-Parallel-Lossless-Compression-for-GPUs: Talk about Zip compression, but Zip uses various algorithms, the most common is inflate/deflate. Roughly speaking it uses chunks of data so you could do more than one chunk at a time. Might not compress as well as going through the entire file, you’re probably going to create chunks that are non-optimal. |