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Author Topic: Bootchart set [3.4.1]  (Read 2230 times)

Offline curaga

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Bootchart set [3.4.1]
« on: February 05, 2011, 10:30:28 AM »
It's been a while since the last "official" bootchart was posted, at the release of TC 2.8 IIRC. Here's a new set for 3.4.1, running on Qemu (software) to capture the effect of a slow single core cpu.

Qemu HW was at defaults, Pentium 2, 128mb ram.
Only the base is measured, no extensions or backup around.

Notes:
- CPU usage is topped nearly all the time. That's good, being cpu-limited we're as fast as we can on the hw. The boot's clearly well ordered, at least for a single core.
- module loading takes long. There are a few initiatives to do something about this by Alan Jenkins and Carmelo Amoroso.
- adding "embed" shaves off 18% of boot time.
- adding "base" shaves off 13% (of the initial, maximum time). There's clearly some optimization possible here.
- adding "norestore" shaves about 3%.
- ditto for "nofstab". This will probably take longer on hw with many drives.
- "noswap" is nearly a no-op, there being no swap to enable.
- adding "nozswap" saved nearly nothing. Thus you shouldn't disable ramzswap just to gain boot time, seeing as there's no tangible gain.

Adding some bootcodes, the time went from 22s to 14s, or a saving of 36%. The kernel seems to take 18% (this includes unpacking the initramfs), which is a good thing as well, pointing that the TC part of the boot is doing fairly well.

Charts ordered by increasing boot codes:
[quiet text], [quiet text embed], [quiet text embed base], [quiet text embed base norestore], [quiet text embed base norestore nofstab], [quiet text embed base norestore nofstab noswap], [quiet text embed base norestore nofstab noswap nozswap]

 
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