13.2.1 for XO-1 using external SD card slot
quozl at laptop.org
Fri Jun 20 21:49:41 EDT 2014
On Fri, Jun 20, 2014 at 09:39:32AM +1000, James Cameron wrote:
> Therefore using an SD card instead of NAND flash should increase I/O
> performance, decrease processor time, and increase available memory.
I've measured the increase in available memory.
With the laptop freshly booted at the activity view and the journal
icon coloured, a program is run that consumes memory in order to
determine how much is available;
- moving the root filesystem from NAND to SDIO is a 7% gain, from 146
MB to 156 MB,
- leaving the root filesystem on NAND and adding 64 MB swap on SDIO is
a 31% gain, from 146 MB to 191 MB,
- moving the root filesystem from NAND to SDIO and adding 64 MB swap
on SDIO is a 41% gain, from 146 MB to 206 MB.
A visualisation of the results:
The test program:
Measurement was the anon-rss in the kernel OOM message, e.g.
[ 761.307460] Killed process 937 (oom) total-vm:197692kB, anon-rss:183048kB, file-rss:4kB
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