Date: Sun, 28 Oct 2001 19:06:33 EET From: Maxim Sobolev <sobomax@mail.ru> To: rwatson@FreeBSD.ORG Cc: cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: ports/devel/ORBit Makefile ports/devel/ORBit/files patch-src::IIOP::giop-msg-buffer.c Message-ID: <E15xtOb-0002Me-00@smtp2.port.ru> In-Reply-To: <Pine.NEB.3.96L.1011028090805.15623B-100000@fledge.watson.org>
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On Sun, 28 Oct 2001 09:20:32 -0500 (EST), Robert Watson wrote:
> =
> On Sun, 28 Oct 2001, Maxim Sobolev wrote:
> =
> > On Fri, 26 Oct 2001 13:22:44 -0400 (EDT), Robert Watson wrote:
> > > =
> > > Are you exceeding UIO_MAXIOV entries in the array? Right now, I thin=
k
> > > it's 35, which for dynamically generated entries, could be too small.
> > > That error will result in EINVAL, and is documented in the man page.
> > =
> > Yes, I've already been clued about this, though it's not a 35, but
> > 1,024. :) =
> =
> Hmm. I have no idea where the number 35 came from. :-) Maybe another
> platform -- I notice that Solaris actually sets it to 16:
It seems that it's the value of KERN_IOV_MAX from sys/sysctl.h.
> /usr/include/limits.h:#define IOV_MAX _XOPEN_IOV_MAX
> /usr/include/limits.h:#define _XOPEN_IOV_MAX 16 /* max #iovec/p=
rocess with readv()/writev() */
> =
> My local Linux box has:
> =
> ...
> linux/uio.h: * UIO_MAXIOV shall be at least 16 1003.1g (5.4.1.1)
> ...
> #define UIO_MAXIOV 1024
> #if 0
> #define UIO_MAXIOV 16 /* Maximum iovec's in one operation =
> 16 matches BSD */
> /* Beg pardon: BSD has 1024 --ANK */
> #endif
I doubt that Linux is really enforces this limit, because if it
does, then the ORBit would be broken there as well. BTW, could you
please do me a favor and run the following program on your Linux
box and send me its output? It tests and reports real value of the
limit.
#include <sys/types.h>
#include <sys/uio.h>
#include <fcntl.h>
#include <stdio.h>
int main()
{
int fd, i; =
static struct iovec iovecs[16385];
if ((fd =3D open("/dev/null", O_WRONLY)) < 0)
exit(1); =
for (i =3D 1; i < 16386 && writev(fd, iovecs, i) >=3D 0; i++);
printf("%d\n", i - 1);
close(fd); =
exit(0); =
}
-Maxim
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