Why is iterating over a file twice faster than reading it into memory and computing twice?
I’m comparing the following
performance
Diffing two big text files
I have two big files (6GB each). They are unsorted, with linefeeds (n) as separators. How can I diff them? It should take under 24h.
Why is kworker consuming so many resources on Linux 3.0.0-12-server?
Last Friday I upgraded my Ubuntu server to 11.10, which now runs with a 3.0.0-12-server kernel. Since then the overall performance has dropped dramatically. Before the upgrade the system load was about 0.3, but currently it is at 22-30 on an 8 core CPU system with 16GB of RAM (10GB free, no swap used).
What’s the progress regarding improving system performance/responsiveness during high disk I/O?
Whenever there is high disk I/O, the system tends to be much slower and less responsive than usual. What’s the progress on Linux kernel regarding this? Is this problem actively being worked on?
Fast way to build a test file with every second listed in YYYY-mm-dd HH:MM:SS format
I want to create a large test file with lines containg dates listed by the second, but my method is taking inordinately long… (or at least, that’s how it feels 🙂 … 43 minutes to create only 1051201 lines. 20.1 MB file….
What are the pros and cons of badblock’s two non-destructive tests?
I use badblocks to test my 32GB class-10 microSD card that I use to boot my RPi. I already have a functioning file system on it, so I don’t want to scan it with the -w option (destructive read-write test).
Why does rename() take longer when fsync() is called first?
In this test, why does rename() take longer when fsync() is called first?
Grep of many keywords over many files: speeding it up
I am currently facing a “performance problem” while using grep. I am trying to locate the occurrences of many (10,000+) keywords in many (think Linux kernel repository size) files.
The objective is to generate a kind of index for each keyword:
What are the exact differences between awk and cut with grep?
We know that we can get the second column of the line we want from a file using these two techniques: awk '/WORD/ { print $2 }' filename or grep WORD filename| cut -f 2 -d ' ' My questions are: What are the differences between the two commands above? Which one has the best … Read more
Is there a fastest way to shutdown the system?
Or is shutdown -h now the fastest it can get?