* PIPE questions for Linux 2.4 setup
@ 2009-05-21 14:56 Ad van den Broek
2009-05-21 19:51 ` Glynn Clements
0 siblings, 1 reply; 2+ messages in thread
From: Ad van den Broek @ 2009-05-21 14:56 UTC (permalink / raw)
To: linux-c-programming
Dear C/Linux friends,
We wanted to increase PIPE_SIZE (from 4K to 8K on linux 2.4 on an AMD
LX800 system).
The result is a segmentation error as soon as Read() is reading more
data than 4K
from the pipe.
So pipe data seems to be damaged.
If we change PIPE_SIZE back tot 4K everything is running fine.
Question-1: Any suggestion to prevent this segmentation error ?
* PIPE_SIZE
If you look in the linux kernel code for PIPE_SIZE
("include/linux/pipe_fs_i.h") you find:
#define PIPE_SIZE PAGE_SIZE
I don't know if #define PIPE_SIZE PAGE_SIZE is necessary or just a
simple shortcut.
Question-2: Is it OK if PIPE_SIZE > PAGE_SIZE ?
* PAGE_SIZE
Question-3: Is it OK to increase Page_size on linux 2.4 on AMD LX800 system ?
Which aspects are limiting the user to config the PAGE_SIZE ?
--
With best regards,
Ad van den Broek
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: PIPE questions for Linux 2.4 setup
2009-05-21 14:56 PIPE questions for Linux 2.4 setup Ad van den Broek
@ 2009-05-21 19:51 ` Glynn Clements
0 siblings, 0 replies; 2+ messages in thread
From: Glynn Clements @ 2009-05-21 19:51 UTC (permalink / raw)
To: AdvandenBroek.nl; +Cc: linux-c-programming
Ad van den Broek wrote:
> Dear C/Linux friends,
>
> We wanted to increase PIPE_SIZE (from 4K to 8K on linux 2.4 on an AMD
> LX800 system).
> The result is a segmentation error as soon as Read() is reading more
> data than 4K
> from the pipe.
> So pipe data seems to be damaged.
> If we change PIPE_SIZE back tot 4K everything is running fine.
> Question-1: Any suggestion to prevent this segmentation error ?
>
> * PIPE_SIZE
> If you look in the linux kernel code for PIPE_SIZE
> ("include/linux/pipe_fs_i.h") you find:
> #define PIPE_SIZE PAGE_SIZE
> I don't know if #define PIPE_SIZE PAGE_SIZE is necessary or just a
> simple shortcut.
> Question-2: Is it OK if PIPE_SIZE > PAGE_SIZE ?
>
> * PAGE_SIZE
> Question-3: Is it OK to increase Page_size on linux 2.4 on AMD LX800 system ?
> Which aspects are limiting the user to config the PAGE_SIZE ?
The page size is hardcoded in silicon; you can't change it in
software.
And the kernel itself no longer refers to PIPE_SIZE (it did in earlier
2.6 versions), so there's not much point in changing it.
--
Glynn Clements <glynn@gclements.plus.com>
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2009-05-21 14:56 PIPE questions for Linux 2.4 setup Ad van den Broek
2009-05-21 19:51 ` Glynn Clements
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