OS/2, eCS & ArcaOS - Technical > Storage

JFS cache sizing, and system "speed-up"

<< < (2/8) > >>

roberto:
You are right in everything, but my question is have you tried it?
As you said, it affects fat
I have tried to copy a folder with usb 2.0 to fat32 and it took me 24 minutes at 1120 bps fc 2.40 and to a usb 3.0 with the same card it takes 33 minutes at 780 bps

saludos

Doug Bissett:
FAT is not FAT32. They are different drivers, with different parameters, and different cache. Using incorrect cache size probably just uses the default size, but it could also just drop the higher bits, and use whatever is left over. If that turns out to be something usable, it will likely work.

No, I haven't tried it. I no longer use FAT, except for the ArcaOS USB stick installer. Working with USB is affected by far too many outside factors, to even consider doing a copy to test speed. Do it 1,000 times, after rebooting each time, with consistent results, and I may find a reason to try it.

Roderick Klein:

--- Quote from: Dariusz Piatkowski on October 21, 2021, 09:58:16 pm ---Hi Doug,


--- Quote from: Doug Bissett on October 21, 2021, 07:16:45 pm ---...

--- Quote ---The apps are loading consistently faster, on multiple attempts.
--- End quote ---

A lot of that "improvement" depends on timing. If the program parts have not been flushed from the cache, the load time is faster (even when using a small cache). Using a larger cache does increase the probability that most of it will still be there, but it depends on what you do between starts...
--- End quote ---

So this point here is actually the crux of what I was trying to improve upon.

Consider a set of applications that you normally run, in my case that normally is a mix of:

1) FF
2) Thunderbird
3) Lotus 1-2-3
4) AOO
5) VSE & IBMCPP & GCC (compilation)
6) PMView

Therefore, by increasing the size of the cache (if the upper memory is rarely used otherwise) allows me to try to pull in more of that working set into the cache, and hopefully convert that into a quicker responding system.

In my case, that appears to have been the result of tripling the size of the cache, with the matching increase in the buffer settings.

Of course that that not mean ALL of these apps and their data (heck, FF has a 512M disk cache) are always there, the cache will of course always continue to be shuffled around as needed.

--- End quote ---

Why is standard Sysbench not sufficient ? Its much more consistant. It tests small file I/O large file I/O.  Also it measures the timing very accurate!

Dariusz Piatkowski:
Hi Roderick,


--- Quote from: Roderick Klein on October 29, 2021, 01:06:28 pm ---Why is standard Sysbench not sufficient ? Its much more consistant. It tests small file I/O large file I/O.  Also it measures the timing very accurate!

--- End quote ---

...because SysBench and diskio measure the raw speed of the hardware and mostly bypass the cache I believe (there is a single cache/bus xfer test in both).

So the attempt here is to optimize the 'runtime' environment by balancing the raw speed of the storage device (that being a SSD in my case) with the system resources (4Gig of RAM) in order to avoid a constant storage device seek for the pertinent data (increasing the cache should allow the most recently used stuff to be available much quicker).

In other words: it's not about sheer performance, rather it's about how all the various controls available to us can produce better application performance.

roberto:

--- Quote from: Doug Bissett on October 29, 2021, 02:44:05 am --- Do it 1,000 times, after rebooting each time, with consistent results, and I may find a reason to try it.

--- End quote ---
You will have to wait about six months for me to try it a thousand times, but for everyone else I leave you a file with instructions on how you can make it consistent each boot.

-Dariusz I agree 100% with your comments from the sysbench ...

saludos

Navigation

[0] Message Index

[#] Next page

[*] Previous page

Go to full version