On Friday 01 June 2007 04:26, Dave Jones wrote:
> On Tue, May 29, 2007 at 09:47:53AM +0800, Yang Sheng wrote:
> > On Tuesday 29 May 2007 06:52, Randy Dunlap wrote:
> > > On Mon, 28 May 2007 15:03:10 +0800 Yang Sheng wrote:
> > > > Why we need this:
> > > >
> > > > It can speed up the calling of initcalls, especially useful for some
> > > > embed device.
> > >
> > > Can you give concrete example(s) of why we need this?
> > > Any real configs/hardware where it helps and how much it helps.
> >
> > We didn't got the precise data at hand now, because we should build a
> > complete stable initcall dependence relationship for it, but we can't do
> > it now.
> >
> > But we have done a relative stable test in a common x86_64 machine, with
> > 2 threads and one dependence relation(pnpacpi_init depends on pnp_init
> > and acpi_init). The result is the time spending on initcall calling
> > reducing from about _5s_ to _2s_ (make the kernel with the defconfig).
> > We analyzed the dmesg and found the most of time was save by run
> > ide_generic_init and piix_init in parallel.
> >
> > Of course the dependence in the test case is not sufficient, but the
> > effect is shown.
> >
> > We think this patch would be very useful in some embed deviced which
> > requires fast boot speed. Some server may benefit too because of it's
> > long time for device initiation.
>
> If we decide to do this, we should also introduce a way to disable it
> at runtime with initcall=noparallel or something. Why?
> Because right now when people say "my computer hangs during bootup"
> we can ask them to boot with initcall_debug and usually find out
> the last thing it did before it locked up. If we parallelise this,
> the output will be a lot harder to decipher.
Thank you for the advice. I will introduce a parameter to do this.
But what's about idea itself? I don't know whether people like this... It
required a little more work on initcall writing.
Maybe we could limit the multithread part in device_initcall? For it seems the
most time consumed here, and the others in total just less than 1s(at least
on my machine).
Thanks.
--
regards
Yang, Sheng
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
