| HN Mirror

## Fired `nnn` in my home dir. - all cached, no major page faults ~$ /usr/bin/time -v nnn Command being timed: "nnn" User time (seconds): 0.00 System time (seconds): 0.00 Percent of CPU this job got: 0% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:03.77 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 3400 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 274 Voluntary context switches: 6 Involuntary context switches: 1 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 ~$ ## Fired `nnn` on an external disk root in du mode, went into a subdir, came back to root. - no major page faults - File system inputs: 14680 - 220 KB cached extra ~$ /usr/bin/time -v nnn -S /media/vaio/49462fdf-010c-40cc-89db-ef125e7dae99/tmp/ Command being timed: "nnn -S /media/vaio/49462fdf-010c-40cc-89db-ef125e7dae99/tmp/" User time (seconds): 0.02 System time (seconds): 0.27 Percent of CPU this job got: 3% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:08.30 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 3620 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 337 Voluntary context switches: 576 Involuntary context switches: 2 Swaps: 0 File system inputs: 14680 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 ~$ ## Fired `nnn` again (around 2 mins later, I was formatting the above text) on the external disk root in du mode. - File system inputs: 0 ** So even between 2 distinct instances of nnn, _all_ the data fetched in the first instance remained cached. ~$ /usr/bin/time -v nnn -S /media/vaio/49462fdf-010c-40cc-89db-ef125e7dae99/tmp/ Command being timed: "nnn -S /media/vaio/49462fdf-010c-40cc-89db-ef125e7dae99/tmp/" User time (seconds): 0.00 System time (seconds): 0.01 Percent of CPU this job got: 0% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:02.31 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 3616 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 329 Voluntary context switches: 5 Involuntary context switches: 0 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 ~$

Yes, I know there is a cache. I went into great detail about it. That wasn’t what I asked you to prove.

What we were arguing about was the L2 cache - which you argued could hold a 2GB file (insanity I call it) and you’re still not proving that point of yours. In fact you’re not even checking if it’s cached in the system memory (there are syscalls to do that), you’re just checking application performance. While it’s pretty obvious that result would have been due to caching it would have been easy to prove that more conclusively by even just flushing the cache (I assume you actually know how to do that? Hint: you can just write to the /proc directory from your shell to do that. It’s easy) and then repeating the test; but You didn’t even do that!

You’re testing is so rudimentary at covering the cases you’re making claims against it’s laughable. you’ve not even begun to address the “processor memory” point you were arguing.

But I honestly think we should just leave it here. You don’t need to be an expert in kernel design nor practical experience in write file systems to write a decent file manager, so all of this arguing is pointless. I just ask that you aren’t so quick to judge other solutions when it’s painfully obvious there are massive gaps in your own understanding.