Re: next vforkup chapter: lwpctl

[Garrett Cooper <yanegomi%gmail.com@localhost>]

On Thu, Feb 17, 2011 at 4:38 PM, Mindaugas Rasiukevicius
<rmind%netbsd.org@localhost> wrote:
> Garrett Cooper <yanegomi%gmail.com@localhost> wrote:
>> >
>> > But what, that uses LWPCTL, are you actually supposed to be doing after
>> > vfork()?  Whack some environment variables and some globals -- maybe --
>> > then exec*().  What else is legitimate?
>> >
>> > If it doesn't slow down vfork, great, fix whatever.  But vfork
>> > performance really is critical.  Look how much slower, for example,
>> > FreeBSD builds the system than we do.  vfork is a huge part of that.
>>
>> Hi Thor,
>>     Do you have performance metrics to back up your statement below
>> about `FreeBSD build[ing] the system slower than we do' (paraphrased)?
>
> http://www.netbsd.org/~ad/5.0/img15.html
>
> Note: it uses the same toolchain (i.e. same make, gcc, etc).
>
> However, I suppose FreeBSD team is aware of these.

Mindaugas,

    Thanks for the details! I was looking for this (I couldn't find
what Thor was referring to on the lists with a 45 or so minute Google
search; it was turning up a lot of noise about Xen on the mailing
lists :)..).
    It would be interesting to see how well FreeBSD fares now because
7.1 was before the ULE scheduler was setup as the default scheduler. A
lot of work went into making that robust and scalable in 7.2 by
jeffr@, jhb@, kris@, etc; one of the big announcements was made at a
little before 7.0-RELEASE [1] and at MeetBSD 2008 [2] by kris@ when he
was still actively working with the project :/... Things also improved
again with scaling in FreeBSD 8.x, and there's work in the pipeline
for 9.0-RELEASE to get rid of vm-locking which seems to have
qualitatively yielded performance gains on the 2 workstations and 1
server I have FreeBSD CURRENT installed on and actively work with.
    If I can get things up and running like someone did for the NetBSD
slides above with FreeBSD CURRENT and NetBSD CURRENT on my amd64 test
machine (directions welcome :)..), I'll give the tests a shot again to
see how divergent the performance results are between the two BSDs in
this area.
Thanks!
-Garrett

1. http://people.freebsd.org/~kris/scaling/7.0%20Preview.pdf
2. http://www.youtube.com/watch?v=Mfb5_uG7BCA