Quoting Erik Josefsson (2019-06-23 07:42:24) > Hi Andy, thanks for taking time and for your advise! > > On 6/22/19 10:22 PM, Andy Smith wrote: > > Hi Erik, > > > > On Fri, Jun 21, 2019 at 03:02:46PM +0200, Erik Josefsson wrote: > >> Maybe flashbench cannot tell me anything about that anyway? > >> > >> Are there other tools? > > I'm not familiar with flashbench. I like fio. It's available in > > Debian. > > > > I like to do the following tests. Example fio command line follows > > for each.
[ details snipped] > Teres-I has one MicroSD slot, one HDMI and two USB ports. > > Is it meaningful to test the SD cards with an USB-adapter? (the MicroSD > slot would be occupied by the SD card the machine is running from/on) Testing SD cards on a different controller may help understand _potential_ features of cards, but not _actual_ reachable potentials. If you prefer an analogy: Reading in a magazine that some Formel-1 driver can cut a corner while driving 60km/h in same model car as yours does not mean that you can expect to cut that same corner at that speed: Depends not only on the vehicle (disk device) but also on the driver! > > Of those figures, I consider the random ones more important in most > > configurations. i.e. if I had to choose between a device that > > supported a bit higher sequential read/write but much lower random > > read/write, I'd rather have the random read/write, because that > > tends to have more impact on interactive usage than sequential. > > Yes, going back and forth between Thunderbird and Firefox while > copying text snippets from one app to the other sometimes ends in a > mouse pointer freeze. > > That's basically what I do most of the time... Biggest speed gain (on a limited computer like Teres-I) is likely had with changing to less ressource hungry tools. Instead of Firefox try GNOME Web (apt install epiphany-browser). It uses the rendering engine "Webkit" so is likely to handle most websites. For an radically lighter browser rendering fewer real-world websites properly and with an arguably less friendly user interface, try Surf. A lighter alternative with ok UI and somewhat decent rendering engine is Netsurf, but unfortunately that one won't make it into Debian Buster. Instead of Thunderbird try Balsa or Claws Mail. > > SD cards tend to have poor random IO speed so I would never use one > > for general purpose computing if I could use an HDD or SSD instead. > > > If random IO speed most likely is the real bottle neck, do you know of > any particular brand/label/kind/category of MicroSD card that is > significantly better than others in that regard? https://github.com/ThomasKaiser/Knowledge/blob/master/articles/A1_and_A2_rated_SD_cards.md (this is perhaps 5th time I share that link with you; 2nd on this list) > Not sure if chasing some microseconds of better performance will make > a difference, but if it is anything like parking with a heavy truck > with heavy trailer in a small parking lot with other cars, then I > guess a microsecond extra is just as important as an extra centimeter > :-) > > > > > > To give you some idea of what decent SSDs manage: > > > > > > http://strugglers.net/~andy/blog/2019/05/29/linux-raid-10-may-not-always-be-the-best-performer-but-i-dont-know-why/ > > > > I don't think I can make Teres-I boot from an external SSD. Through the USB2 interface you can. Won't reach the full potentials of SSD (see Formel-1 analogy above) but may still beat SD-cards. You cannot _boot_ via USB2 interface but you can store your data there which helps some scenarios (e.g. possibly helps Firefox hanging, as that might be due to its working on cache data below your $HOME. - Jonas -- * Jonas Smedegaard - idealist & Internet-arkitekt * Tlf.: +45 40843136 Website: http://dr.jones.dk/ [x] quote me freely [ ] ask before reusing [ ] keep private
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