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startup reduction times with syzygy

People that I’ve told about the work with syzygy that I’ve been doing have, almost universally, two reactions:

  1. That’s cool!  (Thanks; I did very little work for it!)
  2. How does that translate into startup time?

Assuming that a 40% reduction in page faults leads to a 40% reduction in startup time is not reasonable, but surely there should be some reduction in startup time, right?  I finally benchmarked this today using the about:startup extension; these numbers are from cold start, freshly rebooted both times:

Version main sessionRestored firstPaint
Trunk build 125 1733 1671
Optimized build 125 1639 1577

So a 40% reduction in page faults translates into ~6% reduction in startup time; not stellar, but not too bad either.

The next step is making sure this all works with PGO builds on Windows. Then we get to have a discussion about whether to incorporate this into the regular builds and getting all the infrastructure on build machines.


  1. Harsh86

    I guess it depends on how slow of a computer you have. I should imagine it will make a bigger impact on a computer that always has its hard drive thrashing for reason what so ever, such as my work laptop.

    Anyhow great work.

    Posted on 19-Sep-11 at 9:21 pm | Permalink
  2. The win varies with disk speed, is this on SSD?

    Posted on 19-Sep-11 at 9:37 pm | Permalink
  3. nfroyd

    Yes, this is on an SSD. Might be more significant on a mechanical hard drive.

    Posted on 19-Sep-11 at 9:48 pm | Permalink
  4. smoohta

    First of all- great job 🙂

    Second- were this measurements made on the Win7 SSD laptop you mentioned in the previous post? if so, have you thought about measuring it on a non-ssd machine and seeing if that makes a bigger difference to start-up time?

    Posted on 19-Sep-11 at 9:48 pm | Permalink
  5. Nathan Froyd

    Yeah, this was on that laptop. I will experiment with my desktop machine (old, creaky 80GB drive) and see if that makes a difference.

    Posted on 19-Sep-11 at 9:50 pm | Permalink

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