Re: ARM sim patch: increase default target memory

Andrew Cagney
2002-03-19T16:39:44Z

> On Tue, 2002-03-19 at 07:46, Andrew Cagney wrote:
>
>> The number is a compromise between a fast simulator startup, sufficient
>> memory for a typical simulation and unnecessary VM grab. It was also
>> found to be sufficient for the basic GDB and GCC tests.
>
>
> Unfortunately this isn't true anymore. gcj is part of GCC and 2MB is
> not enough space.

As I said a compromise for the ``basic'' gcc tests. I recall this value
being put up once before and people complaining that the basic tests
slowed down and GDB grabbed too much memory.

>> From memory, he Java tests run on the MIPS (and PPC?) simulators and
>> yet there haven't been problems. The MIPS defaults to 2mb, the PPC 1mb.
>
>
> (just MIPS) The default runtime requirements have grown since the early
> days. 8MB appears to be a very comfortable amount of space, although
> with some experimentation this could probably be brought down.
>
>
>> I don't think that re-compiling GDB is the correct way for a user to
>> change the size of simulator memory. Instead the user should be able to
>> fix it at run time. I think that is the real bug here.
>
>
> Yes, I agree that this is a bug, which is why I filed a case against it.

We're going to degenerate into semantics :-)

Arm can't change its memory size at run time. This is the bug that hurt
you - you had to change a compile time constant to fix your problem and
that simply shouldn't have been necessary. Remember, the other
simulators don't have this problem as -m<blah> can be used.

As a separate issue, it is probably time to review the default memory
size for all the simulators. Should they all be increased (to again be
consistent)? Should the GDB builder be allowed to
--enable-sim-memory-size=BLAH this?

Andrew