Re: XO-1 vs Sugar 0.104 performance, and swap to NAND Flash
On Wed, Apr 08, 2015 at 07:35:34PM -0400, Kevin Gordon Gmail wrote: Perhaps silly Q... Any benefit just putting swap and static content on the SD? No question is silly. ;-) I'm guessing you are asking about performance, or response times. If so, the short answer is no. Details below. If you are looking for benefits other than performance, the main benefit is total size. NAND flash is only 1 GB. By adding an 128 GB SD card, the total content stored on the XO-1 can increase dramatically. -- Details #1 It has to do with when data moves, and how much concurrency occurs. A counter question is ... when is it that the XO-1 will both read from NAND flash _and_ from SD card at the same time? Probably never. Data that moves from NAND flash to memory happens during Sugar startup, and the first time an activity is started. It can also happen if a different activity is started. Once an activity is started, usually no further demand occurs. Memory data that moves to swap does so because it isn't being used. In my tests of Sugar 0.104 on Fedora 18, about 12 MB of data moves to swap, and no more. This happens during Sugar startup, and the first activity startup, then it doesn't happen any more until the next reboot. This data generally does not return from swap. So with swap on SD card, it only benefits during Sugar startup and first activity startup, and before content is accessed. Content data, such as videos, web pages, audio, images, and so on, is accessed after the Browse activity has started. So with content on SD card, there should be no significant difference. While the system is capable of much more concurrency (see below), Sugar and the activities just don't make that demand. You could test it by timing how long before content is visible. -- Details #2 Proof the NAND flash and SD card do not block each other. The camera, SD card reader slot, and NAND flash all hang off the CAFE ASIC which presents through a PCI bus to the CPU. Does filling the data channel to one device block the other device in any way? Read test from NAND flash yields about 8 MB/s. When the SD card is doing a read test, a simultaneous read test from NAND flash yields about 5.8 MB/s. The decrease is due to contention for CPU and bus. At the same time, the SD card read test result is mostly unchanged, falling from 6.9 MB/s to 6.6 MB/s. Read from filesystem cache of NAND flash yields about 45 MB/s. When the SD card is doing a read test, a read from filesystem cache of NAND flash yields about 32 MB/s. The decrease is due to contention for CPU and bus. At the same time, the SD card read test result is mostly unchanged, falling from 6.9 MB/s to 6.7 MB/s. This means the bus path to the SD card is mostly idle, and the kernel is waiting for the SD card to respond. So the CAFE ASIC and PCI bus are easily able to handle an aggregate of about 12.4 MB/s, and perhaps much more. -- James Cameron http://quozl.linux.org.au/ ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
interesting new battery technology
Aluminum and Graphite, in an aqueous solution. Can’t wait till it hits the market! http://www.bbc.com/news/science-environment-32204707 ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: XO-1 vs Sugar 0.104 performance, and swap to NAND Flash
Perhaps silly Q... Any benefit just putting swap and static content on the SD? Kg Sent from my currently functioning gadget Original Message From: James Cameron Sent: Wednesday, April 8, 2015 19:31 To: devel@lists.laptop.org; sugar-de...@lists.sugarlabs.org; support-g...@lists.laptop.org Subject: Re: XO-1 vs Sugar 0.104 performance, and swap to NAND Flash What benefit is an SD card on an XO-1? My tests of about 400 starts show some benefit of using an SD card, on activity startup time. The benefits are: - boot time was decreased by several seconds; because of reduced demand for memory, - first activity start after boot was decreased by several seconds; because of reduced demand for memory, - when there is no contention for memory, mean cold activity startup time is decreased by between 1 and 2 seconds; because of both different data rates and no decompression, and; - writing journal entries is slightly faster. There was no benefit on activity startup time where caches were warm; everything needed by the activity was already in memory, so there was no extra wait. The SD card was a SanDisk Ultra 8GB, class 10, 30 MB/s. Sequential read speed on a modern desktop is 18.5 MB/s. But on the XO-1 the speed is 6.3 MB/s. There may be little advantage to using a faster card. For Sugar 0.104 comparing results by activity, between NAND flash and SD card: bundle_id cold warm std ratio tests com.garycmartin.Moon 11.928 10.294 0.492 0.863 24 com.garycmartin.Moon 11.809 10.585 0.516 0.896 24 sd com.jotaro.ImplodeActivity 9.084 9.017 0.498 0.993 24 com.jotaro.ImplodeActivity 9.560 8.904 0.501 0.931 24 sd org.laptop.AbiWordActivity 20.868 16.862 0.376 0.808 24 org.laptop.AbiWordActivity 19.326 16.441 0.277 0.851 24 sd org.laptop.AcousticMeasure 12.330 10.513 0.137 0.853 24 org.laptop.AcousticMeasure 11.854 10.552 0.254 0.890 24 sd org.laptop.Calculate 11.591 9.920 0.120 0.856 24 org.laptop.Calculate 12.152 9.975 0.205 0.821 24 sd org.laptop.HelpActivity 14.654 8.981 0.329 0.613 24 org.laptop.HelpActivity 13.025 9.027 0.345 0.693 24 sd org.laptop.MeasureActivity 16.381 11.364 0.135 0.694 24 org.laptop.MeasureActivity 15.000 11.634 0.344 0.776 24 sd org.laptop.Memorize 17.961 14.550 0.183 0.810 24 org.laptop.Memorize 16.442 14.724 0.240 0.896 24 sd org.laptop.Oficina 12.231 12.029 0.351 0.983 24 org.laptop.Oficina 13.250 12.270 0.585 0.926 24 sd org.laptop.Pippy 8.752 8.202 0.128 0.937 24 org.laptop.Pippy 9.897 8.404 0.467 0.849 24 sd org.laptop.RecordActivity 16.956 12.652 0.145 0.746 24 org.laptop.RecordActivity 15.341 12.501 0.255 0.815 24 sd org.laptop.sugar.Jukebox 9.666 8.986 0.108 0.930 24 org.laptop.sugar.Jukebox 9.821 9.287 0.472 0.946 24 sd org.laptop.sugar.ReadActivity 11.296 10.477 0.165 0.928 24 org.laptop.sugar.ReadActivity 11.080 10.618 0.463 0.958 24 sd org.laptop.TamTamMini 18.628 14.734 0.576 0.791 24 org.laptop.TamTamMini 19.838 14.615 0.288 0.737 24 sd org.laptop.WebActivity 19.425 12.527 0.217 0.645 24 org.laptop.WebActivity 17.935 12.937 0.274 0.721 24 sd tv.alterna.Clock 10.061 7.124 0.123 0.708 24 tv.alterna.Clock 21.226 7.522 0.316 0.354 24 sd ? vu.lux.olpc.Maze 8.366 8.265 0.120 0.988 24 vu.lux.olpc.Maze 8.998 8.646 0.370 0.961 24 sd vu.lux.olpc.Speak 24.555 12.075 0.208 0.492 24 ? vu.lux.olpc.Speak 16.526 11.946 0.358 0.723 24 sd The cold results for Clock and Speak are unexpected, but this may be related to gst-plugin-scan. (Reference: test #6, vs #10) -- James Cameron http://quozl.linux.org.au/ ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: XO-1 vs Sugar 0.104 performance, and swap to NAND Flash
What benefit is an SD card on an XO-1? My tests of about 400 starts show some benefit of using an SD card, on activity startup time. The benefits are: - boot time was decreased by several seconds; because of reduced demand for memory, - first activity start after boot was decreased by several seconds; because of reduced demand for memory, - when there is no contention for memory, mean cold activity startup time is decreased by between 1 and 2 seconds; because of both different data rates and no decompression, and; - writing journal entries is slightly faster. There was no benefit on activity startup time where caches were warm; everything needed by the activity was already in memory, so there was no extra wait. The SD card was a SanDisk Ultra 8GB, class 10, 30 MB/s. Sequential read speed on a modern desktop is 18.5 MB/s. But on the XO-1 the speed is 6.3 MB/s. There may be little advantage to using a faster card. For Sugar 0.104 comparing results by activity, between NAND flash and SD card: bundle_idcoldwarmstd ratio tests com.garycmartin.Moon 11.928 10.294 0.492 0.863 24 com.garycmartin.Moon 11.809 10.585 0.516 0.896 24 sd com.jotaro.ImplodeActivity 9.084 9.017 0.498 0.993 24 com.jotaro.ImplodeActivity 9.560 8.904 0.501 0.931 24 sd org.laptop.AbiWordActivity 20.868 16.862 0.376 0.808 24 org.laptop.AbiWordActivity 19.326 16.441 0.277 0.851 24 sd org.laptop.AcousticMeasure 12.330 10.513 0.137 0.853 24 org.laptop.AcousticMeasure 11.854 10.552 0.254 0.890 24 sd org.laptop.Calculate 11.591 9.920 0.120 0.856 24 org.laptop.Calculate 12.152 9.975 0.205 0.821 24 sd org.laptop.HelpActivity 14.654 8.981 0.329 0.613 24 org.laptop.HelpActivity 13.025 9.027 0.345 0.693 24 sd org.laptop.MeasureActivity 16.381 11.364 0.135 0.694 24 org.laptop.MeasureActivity 15.000 11.634 0.344 0.776 24 sd org.laptop.Memorize 17.961 14.550 0.183 0.810 24 org.laptop.Memorize 16.442 14.724 0.240 0.896 24 sd org.laptop.Oficina 12.231 12.029 0.351 0.983 24 org.laptop.Oficina 13.250 12.270 0.585 0.926 24 sd org.laptop.Pippy 8.752 8.202 0.128 0.937 24 org.laptop.Pippy 9.897 8.404 0.467 0.849 24 sd org.laptop.RecordActivity 16.956 12.652 0.145 0.746 24 org.laptop.RecordActivity 15.341 12.501 0.255 0.815 24 sd org.laptop.sugar.Jukebox 9.666 8.986 0.108 0.930 24 org.laptop.sugar.Jukebox 9.821 9.287 0.472 0.946 24 sd org.laptop.sugar.ReadActivity 11.296 10.477 0.165 0.928 24 org.laptop.sugar.ReadActivity 11.080 10.618 0.463 0.958 24 sd org.laptop.TamTamMini 18.628 14.734 0.576 0.791 24 org.laptop.TamTamMini 19.838 14.615 0.288 0.737 24 sd org.laptop.WebActivity 19.425 12.527 0.217 0.645 24 org.laptop.WebActivity 17.935 12.937 0.274 0.721 24 sd tv.alterna.Clock 10.061 7.124 0.123 0.708 24 tv.alterna.Clock 21.226 7.522 0.316 0.354 24 sd ? vu.lux.olpc.Maze 8.366 8.265 0.120 0.988 24 vu.lux.olpc.Maze 8.998 8.646 0.370 0.961 24 sd vu.lux.olpc.Speak 24.555 12.075 0.208 0.492 24 ? vu.lux.olpc.Speak 16.526 11.946 0.358 0.723 24 sd The cold results for Clock and Speak are unexpected, but this may be related to gst-plugin-scan. (Reference: test #6, vs #10) -- James Cameron http://quozl.linux.org.au/ ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: [Sugar-devel] XO-1 vs Sugar 0.104 performance, and swap to NAND Flash
On 07/04/15 22:47, James Cameron wrote: The testing scripts can be made available if anybody else would like to replicate the results. I'd be curious to look at your scripts and try to replicate some results with our builds. git clone git://dev.laptop.org/users/quozl/test-startup-time.git Look at the file HOWTO. Somewhat unfinished work. Do ask any questions you may have. Thanks a lot for your detailed tests! No worries. Interesting details! I'd be interested to see if porting Browse to the newer webkit 2 and what effect the perf improvements there would offer ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Ubuntu uxo
How would I make a build for xo-1 using uxo tool from git Thanks ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
