Re: [PATCH v1 4/4] accel/tcg: increase default code gen buffer size for 64 bit

[Igor Mammedov]

On Thu, 27 Feb 2020 04:56:46 -0800
Richard Henderson <address@hidden> wrote:

> On 2/27/20 4:31 AM, Alex Bennée wrote:
> >> It does not make sense for a linux-user chroot, running make -jN, on just 
> >> about
> >> any host.  For linux-user, I could be happy with a modest increase, but 
> >> not all
> >> the way out to 2GiB.
> >>
> >> Discuss.  
> > 
> > Does it matter that much? Surely for small programs the kernel just
> > never pages in the used portions of the mmap?  
> 
> That's why I used the example of a build under the chroot, because the 
> compiler
> is not a small program.
> 
> Consider when the memory *is* used, and N * 2GB implies lots of paging, where
> the previous N * 32MB did not.
> 
> I'm saying that we should consider a setting more like 128MB or so, since the
> value cannot be changed from the command-line, or through the environment.

That's what BSD guys force tb-size to, to speed up system emulation.

> 
> 
> r~
>