"3.5GB user address space" option.

"3.5GB user address space" option.

[Oleg A. Yurlov]

        Hi, folks,

        How  I  can  use  3.5GB  in my apps ? I try malloc() and get error on 2G
bounce... :-(

        Hardware - SMP server, 2Gb RAM, 8Gb swap, kernel 2.4.12aa1.

--
Oleg A. Yurlov aka Kris Werewolf, SysAdmin      OAY100-RIPN
mailto:kris@spylog.com                          +7 095 332-03-88

Re: "3.5GB user address space" option.

[Rik van Riel]

On Thu, 18 Oct 2001, Oleg A. Yurlov wrote:

>         How I can use 3.5GB in my apps ? I try malloc() and get
> error on 2G bounce... :-(

You may want to use the 'hoard' memory allocation library,
it seems a bit smarter than glibc's malloc in getting all
the address space your program wants.

1) install libhoard
2) export LD_PRELOAD=libhoard.so
3) run the program

cheers,

Rik
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Re: "3.5GB user address space" option.

[H. Peter Anvin]

Followup to:  <1981072193242.20011018021819@spylog.com>
By author:    "Oleg A. Yurlov" <kris@spylog.com>
In newsgroup: linux.dev.kernel
>
> 
>         Hi, folks,
> 
>         How  I  can  use  3.5GB  in my apps ? I try malloc() and get error on 2G
> bounce... :-(
> 
>         Hardware - SMP server, 2Gb RAM, 8Gb swap, kernel 2.4.12aa1.
> 

Get a 64-bit CPU.  You're running into a fundamental limit of 32-bit
architectures.

	-hpa
-- 
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Re: "3.5GB user address space" option.

[Andrea Arcangeli]

On Wed, Oct 17, 2001 at 09:38:35PM -0700, H. Peter Anvin wrote:
> Followup to:  <1981072193242.20011018021819@spylog.com>
> By author:    "Oleg A. Yurlov" <kris@spylog.com>
> In newsgroup: linux.dev.kernel
> >
> > 
> >         Hi, folks,
> > 
> >         How  I  can  use  3.5GB  in my apps ? I try malloc() and get error on 2G
> > bounce... :-(
> > 
> >         Hardware - SMP server, 2Gb RAM, 8Gb swap, kernel 2.4.12aa1.
> > 
> 
> Get a 64-bit CPU.  You're running into a fundamental limit of 32-bit
> architectures.

Actually 3.5G per-process is theoretically possible using a careful
userspace as Rik suggested with -aa after enabling the proper
compile time configuration option. So for apps that needs say 3G
per-process it should work just fine. But of course for anything that
needs more than that 64bit is the right way to go :)

Andrea

Re[2]: "3.5GB user address space" option.

[Oleg A. Yurlov]

        Hi,

Thursday, October 18, 2001, 1:09:14 PM, you wrote:

AA> On Wed, Oct 17, 2001 at 09:38:35PM -0700, H. Peter Anvin wrote:
>> Followup to:  <1981072193242.20011018021819@spylog.com>
>> By author:    "Oleg A. Yurlov" <kris@spylog.com>
>> In newsgroup: linux.dev.kernel
>> >
>> > 
>> >         Hi, folks,
>> > 
>> >         How  I  can  use  3.5GB  in my apps ? I try malloc() and get error on 2G
>> > bounce... :-(
>> > 
>> >         Hardware - SMP server, 2Gb RAM, 8Gb swap, kernel 2.4.12aa1.
>> > 
>> 
>> Get a 64-bit CPU.  You're running into a fundamental limit of 32-bit
>> architectures.

AA> Actually 3.5G per-process is theoretically possible using a careful
AA> userspace as Rik suggested with -aa after enabling the proper
AA> compile time configuration option. So for apps that needs say 3G
AA> per-process it should work just fine. But of course for anything that
AA> needs more than that 64bit is the right way to go :)

        Thanks to all, problem solved :-) Now apps can use about 3.5G.

AA> Andrea
AA> -
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--
Oleg A. Yurlov aka Kris Werewolf, SysAdmin      OAY100-RIPN
mailto:kris@spylog.com                          +7 095 332-03-88