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Week 8 [ Mon 12 Jul 2010 - Sun 18 Jul 2010 ]

Day 1 [ Mon 12 Jul 2010 ]

Git commit: a8e9adfd4a8e3775c227a5f8f8138ef9d2a9d922

I started out today by creating a new local branch and removing any non-critical code, constantly comparing what I had with the old driver. Eventually I reached a point where the new driver was very very similar to the old one, yet it still didn't work. I then remembered that Marty suggested that there might be alignment issues. And indeed there were. Using malloc_dma() and an alignment of 32 got the driver working and I finally booted a PXELINUX + DSL combo. Yay :)

Tomorrow I'll post some speed comparisons between the new and the old driver and start cleaning up the code.

Day 2 [ Tue 13 Jul 2010 ]

No coding today, just some tests.

I ran both the old driver and the new one and got the following results ( the test downloads an 100mb image 5 times ):

Old New
12 12
11 11
11 12
11 13
11 62

The new driver does not perform better than the old one does, on the contrary. When I'll start cleaning up the code, I'll also try and optimize to get better performance.

Also, there is probably a bug in the driver since the last image was downloaded in over 60 seconds. Luckily, this behaviour is deterministic making it easier to fix. Plus, I saved the Wireshark dumps and I think they will help too.

I'll spend the rest of the day refreshing my TCP knowledge, I think it'll help when looking at the packet dumps.


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