Firefox/Goals/2010Q1/IO Reduction

Reducing I/O operations on the main thread will remove potential points of hanging that users experience, providing a substantially better user experience to our users. Removing at least 50% of our current I/O operations (as of January 1, 2010) from the main thread.

• Project Lead: sdwilsh
• Project Members: Bjarne, mak, rflint, Unfocused

Status

MISSED. 42 - 43% of the IO has been removed from mozilla-central. Up to 23.4% is real close. See this table for more details

Goals

• Reduce at least 50% of the I/O operations on the main thread (read, write, fsync, fstat) based on a certain set of criteria.

Non-Goals

• Reduce the number of I/O operations that we do

Timeline / Milestones

Initial numbers from v1.2 of the criteria are:

• write counts: 4362
• read counts: 1636
• fsync counts: 47
• fstat counts: 1517
• total count: 7562

Note: You will find 5803 writes in the log, however 1441 of them are due to PR_SetPollableEvent. There is a bug in the DTrace script that we haven't been able to figure out that attributes it to some file when it is actually writing to a named pipe or socket. We don't actually care about this write, so we've adjusted the total to reflect this.

Finishing numbers from v1.2 of the criteria are:

• write counts: 1431
• read counts: 1649
• fsync counts: 19
• fstat counts: 1268
• total count: 4367

Note: You will find 2968 writes in the log, however 1537 of them are due to PR_SetPollableEvent. There is a bug in the DTrace script that we haven't been able to figure out that attributes it to some file when it is actually writing to a named pipe or socket. We don't actually care about this write, so we've adjusted the total to reflect this.

These are the bugs of interest:

Requirements

This work must be landed on mozilla-central by March 31, 2010.

Dependencies

None

Testing

Our normal automated testing should be sufficient here. Numbers of calls are generated by this DTrace script.

Related Projects

None