673258 - Collect systemtap data for I/O on Android

Status: RESOLVED FIXED

(Firefox for Android Graveyard :: General, defect)

Description

[Benjamin Stover (:stechz)]

This is to give us an idea about what we should focus on for reducing startup time.

Comment 1

[(inactive) Jim Chen [:jchen] [:darchons]]

I've managed to build systemtap (with hints from http://www.omappedia.org/wiki/Systemtap), but now I need to learn how to actually use it :D  Looking for good tutorials / sample scripts.

Comment 2

[Mike Hommey [:glandium]]

http://glandium.org/blog/?p=1476

Comment 3

[(inactive) Jim Chen [:jchen] [:darchons]]

Attachment: Output with glandium's I/O script

This was the output generated by glandium's I/O tracking script. Measured after a reboot on a HTC Vision using latest trunk.

First column is the Unix time in us. Second is filename. Third is the page offset being read.

Comment 4

[(inactive) Jim Chen [:jchen] [:darchons]]

Attachment: Cold startup I/O (cached libraries)

I have four sets of data for time spent waiting for I/O during fennec startup under different configurations. I will put up charts made based on these data. This first chart is cold startup with cached libraries.

The data measure time spent waiting on either page fault or file read. From the chart, Y-axis is the list of files accessed, grouped by thread ('rd' denotes file read and 'mm' denotes page fault). X-axis is time relative to start of measurement. In each chart there are three marking lines. They correspond to time of launching, reaching XRE_main, and first painting, respectively, as seen from the error console.

Comment 5

[(inactive) Jim Chen [:jchen] [:darchons]]

Attachment: Hot startup I/O (cached libraries)

The second chart is hot startup with cached libraries.

Comment 6

[(inactive) Jim Chen [:jchen] [:darchons]]

Attachment: Cold startup I/O (unzipped libraries)

The third chart is cold startup with unzipped (noncached) libraries.

Comment 7

[(inactive) Jim Chen [:jchen] [:darchons]]

Attachment: Hot startup I/O (unzipped libraries)

The fourth chart is hot startup with unzipped (noncached) libraries.

Comment 8

[(inactive) Jim Chen [:jchen] [:darchons]]

These data are not relevant anymore in this brave new world of native Fennec that we live in.