On 10/26/2011 10:54 PM, Tom Gall wrote:
In prep for Linaro Connect & the Ubuntu Developers Summit next week I've put together some performance measurements comparing libjpeg8c and libjpeg-turbo compiled with it's libjpeg8 compatibility setting. Quality settings of 95 and 75 are used. Image sizes used are 640x480 and 3136x2352.
Hardware used includes the imx53 QuickStart board by freescale and an intel core 2 duo in my Lenovo T400.
The results can be found here including both the raw numbers and pretty graphs.
https://wiki.linaro.org/TomGall/LibJpeg8
It is my hope that at LC/UDS we will be able to use these numbers to convince ubuntu to reconsider it's switch to libjpeg8 and instead move to libjpeg-turbo. The 2x-4x across the board performance improvement story is compelling not to mention the technical side of it as well.
I doubt that Ubuntu will reconsider this for Precise, but I see that you did schedule a session for UDS/Connect [1]. It would be good, if you could provide relevant information for the session:
- performance data from your wiki in a precise/12.04 environment, not just for arm, but for all supported Ubuntu architectures. Performance data from a natty environment doesn't really help.
How does this compare to a libjpeg8 targeted to newer CPUs? Such a library could be used via hwcap.
- A test rebuild for packages build-depending on libjpeg*-dev. Not sure if this will catch all issues, but it's a start. That should give an estimate for sourceful and sourceless changes needed, and for which packages you'll have to maintain a delta compared to Debian.
Thanks, Matthias
[1] https://blueprints.launchpad.net/libjpeg-turbo/+spec/linaro-gfxmm-libjpeg-tu...