Linux-Development-Sys Digest #776, Volume #8 Thu, 7 Jun 01 13:13:18 EDT
Contents:
Re: thundering herd problem: the REAL scoop (Andrew Gierth)
source code of "hostid" command ("Murphy")
Matt Blaze's CFS on Linux - readdir problem. ("Binesh Bannerjee")
Re: source code of "hostid" command (Josef Moellers)
Re: Linux-2.4.5 ("D. Stimits")
Re: mmap+/dev/zero+madvise(WILLNEED) fails? (Zeljko Vrba)
Highspeed Parallel Interface (Bryan Christianson)
Re: Porting solaris software to Linux ("jamal")
Re: module doesn't load in kernel 2.2.x SMP (Jeseem)
CD/DVD ROM speed - too much noise (Benou)
Re: CD/DVD ROM speed - too much noise (Thomas Steffen)
Re: information (Lew Pitcher)
Re: CD/DVD ROM speed - too much noise (Benou)
FIFO (Jan Pietrusky)
accept freezes (Christophe Dore)
Re: FIFO (Kasper Dupont)
Re: FIFO (Jan Pietrusky)
Re: FIFO (Kasper Dupont)
Re: information (=?iso-8859-1?Q?Andr=E9?= David)
Re: mmap+/dev/zero+madvise(WILLNEED) fails? (M.)
Re: mmap+/dev/zero+madvise(WILLNEED) fails? (Zeljko Vrba)
----------------------------------------------------------------------------
From: Andrew Gierth <[EMAIL PROTECTED]>
Crossposted-To: comp.unix.programmer,comp.unix.bsd.freebsd.misc
Subject: Re: thundering herd problem: the REAL scoop
Date: 07 Jun 2001 02:25:29 +0100
>>>>> "phil" == phil-news-nospam <[EMAIL PROTECTED]> writes:
phil> FreeBSD's kqueue/kevent syscalls could easily be made to solve
phil> this problem.
I think this is harder than it sounds. Since kqueues can't be shared
between processes (at least in -STABLE), you have essentially the same
problem in that you have N processes each with a kevent filter for the
accept, and you have to direct the incoming connection to exactly one
of them; the kernel has no way to choose which is the right one.
IMO descriptor-passing is a better solution, because it puts the
control in the user process rather than relying on kernel guesswork.
--
Andrew.
comp.unix.programmer FAQ: see <URL: http://www.erlenstar.demon.co.uk/unix/>
or <URL: http://www.whitefang.com/unix/>
------------------------------
From: "Murphy" <[EMAIL PROTECTED]>
Subject: source code of "hostid" command
Date: Thu, 7 Jun 2001 11:25:17 +0800
Hi Friend,
Is there someone who knows where I can get the source code of "hostid"
command ? I'm interested in it. Thanks!
------------------------------
From: "Binesh Bannerjee" <[EMAIL PROTECTED]>
Crossposted-To:
comp.os.linux.security,comp.os.linux.misc,comp.os.linux.development.apps
Subject: Matt Blaze's CFS on Linux - readdir problem.
Date: 7 Jun 2001 05:42:38 GMT
Hi.
First of all, I've been trying to subscribe to the mail list,
and have as of yet been unsuccessful. Is it still up?
Now, to the real problem:
I hacked at the CFS source, till I got it to work, and it works...
_basically_... I haven't lost any files, and all the files md5 sum the same,
but, I noticed that when in large CFS'd directories, command completion and
shell metacharacter expansion wasn't working, but ls and friends did work
(I'm running CFS-1.4.1 on Linux 2.4.5 with the out of the box NFS from
RedHat 6.2) I tracked it down to this:
if you read a large CFS directory with readdir it doesn't get
all of the files, but readdir64 will work... Has anyone else
had this problem, and if so, how do I go about fixing it?
Thanks,
Binesh Bannerjee
------------------------------
From: Josef Moellers <[EMAIL PROTECTED]>
Subject: Re: source code of "hostid" command
Date: Thu, 07 Jun 2001 08:01:01 +0200
Murphy wrote:
> =
> Hi Friend,
> =
> Is there someone who knows where I can get the source code of "hostid"
> command ? I'm interested in it. Thanks!
If you have a Linux distribution that comes with source code (as it
should), it should be on one of the CDs. Use "locate hostid" to find out
where exactly the binary is (/usr/bin/hostid), then use "rpm -qf
/usr/bin/hostid" to find out which packet brought you the binary
(util-2.10m-41 on my SuSE 7.0), then use "rpm -qi util" to find the
source rpm (util-2.10m-41.src.rpm on my SuSE 7.0).
-- =
Josef M=F6llers (Pinguinpfleger bei FSC)
If failure had no penalty success would not be a prize
-- T. Pratchett
------------------------------
Date: Thu, 07 Jun 2001 00:19:43 -0600
From: "D. Stimits" <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
Subject: Re: Linux-2.4.5
[EMAIL PROTECTED] wrote:
>
> I have been trying to upgrade from RH2.2.12-20 to kernel 2.4.5. I am
> running an AMD-K6-2 processor with 64mb ram, a CreativeLabs PCI 512 sound
> card, and a Lynksys NIC. The kernel freezes at boot. It only gets as for as
> Uncompressing linux.... Ok boot. This not verbatum but close. I tried 2.4.3
> previously with the same problem. The pathes were unsuccessful.
>
> B.M. Richard
>
> --
> Posted via CNET Help.com
> http://www.help.com/
There are several bugs that might do this (I found one on my machine,
despite the cockroach poison), which are corrected in Alan Cox's ac
series of patches. Try patching with:
ftp://zeus.kernel.org/pub/linux/kernel/people/alan/2.4/patch-2.4.5-ac9.bz2
D. Stimits, [EMAIL PROTECTED]
------------------------------
From: [EMAIL PROTECTED] (Zeljko Vrba)
Subject: Re: mmap+/dev/zero+madvise(WILLNEED) fails?
Date: 7 Jun 2001 06:16:40 GMT
Reply-To: [EMAIL PROTECTED]
On 6 Jun 2001 15:01:41 -0700, M. <[EMAIL PROTECTED]> wrote:
>
> Question is: is this a normal design behaviour? if so, what does the
> EIO error mean? and, is there another way to madvise the OS to keep
> this memory in physical ram rather than on secondary storage?
>
/dev/zero has no secondary storage.. What exactly are you trying to accomplish?
You should probably look into mlock.
------------------------------
From: Bryan Christianson <[EMAIL PROTECTED]>
Subject: Highspeed Parallel Interface
Date: Thu, 07 Jun 2001 18:37:45 +1200
I have a board (Satellite receiver) that delivers output via a DB-25
connector - 8 pins for data and a couple of clock/control pins at LVDS
levels. Data rates could be as high as 100Mbps.
What are my options for getting this data into kernel space where I can
then do something useful with it. I assume I need a board that will
plug into the PCI bus and has some kind of LVDS input interface.
I've had a bit of a hunt around the net for LVDS/PCI boards but mostly
they look too expensive for the budget of my project.
Any help appreciated
Regards
Bryan Christianson
------------------------------
From: "jamal" <[EMAIL PROTECTED]>
Crossposted-To: comp.os.linux.development.apps,comp.unix.programmer,comp.unix.solaris
Subject: Re: Porting solaris software to Linux
Date: Thu, 7 Jun 2001 17:31:26 +0900
Reply-To: "jamal" <[EMAIL PROTECTED]>
Thanks for the replies.
FYI, the software is an online community service consists of several modules
such as
chatting server, messenger servers, email service, BBS etc.
So it is a large program. It use threads, semaphore, share memory etc.
>From information so far, I summarize:
- There is thread/IPC issues
- signal handling
- compiler problem
Another question:
- Someone pointed me GNU autoconf and automake help to create more portable
code
for *NIX application. How well these application help me to o the job as I
know nothing about them.
Regards,
Jamal
"jamal" <[EMAIL PROTECTED]> wrote in message
news:9fhrtj$cho$[EMAIL PROTECTED]...
> Hi ,
>
> I am new in linux or unix programming in general.
> My company has an application written for Windows and Solaris.
> We plan to port it to Linux. So the easiest should be porting
> Solaris version into Linux version. I wonder what the main issues that I
> should take care of for doing the porting.
> Is it just compatibility between solaris system library and linux system
> library or is there any specific
> problem?
> As I know that all unix system should have the similar API right? So in
what
> part they differ?
> For your imformation the solaris software is compiled using sun cc
compiler,
> but there are some error when I tried to compile
> using gcc, so obviously the compiler difference is one of the
consideration.
>
>
> regards
>
> Jamal
>
>
>
>
------------------------------
From: [EMAIL PROTECTED] (Jeseem)
Subject: Re: module doesn't load in kernel 2.2.x SMP
Date: 7 Jun 2001 01:30:35 -0700
[EMAIL PROTECTED] () wrote in message news:<[EMAIL PROTECTED]>...
> In article <[EMAIL PROTECTED]>,
> Jeseem <[EMAIL PROTECTED]> wrote:
>
> > My kernel module has versioning disabled. (the kernel has versioning
> >enabled.)
>
> Wouldn't that be a big problem?
When I enable versioning in my module it loads fine.
May be I am doing something stupid here.
Any help !!
Warm Regards
Jeseem
------------------------------
From: Benou <[EMAIL PROTECTED]>
Crossposted-To: comp.os.linux.hardware
Subject: CD/DVD ROM speed - too much noise
Date: Thu, 7 Jun 2001 11:28:46 +0200
Hi,
I have a brand new DVD ROM drive, and of course, it does make noise!!
Under windows I've found a small utility that can set the maximal speed
from 17X to 4X (4X was "detected" on my drive). This utility is not
optimal, the settings are lost as soon as I insert a new CD (for DVDs
it does not work).
So, is there any way to do the same under linux???
Thanks
--
________________________________________________________________________
Benjamin Forgeau Raum 3032, Denickestr 17, 21073 Hamburg
FSP 4-06 Kommunikationsnetze Tel. +4940 42878 3485 Fax 42878 2941
TU Hamburg-Harburg mailto:[EMAIL PROTECTED]
21071 Hamburg, Germany http://www.tu-harburg.de/et6
________________________________________________________________________
------------------------------
From: Thomas Steffen <[EMAIL PROTECTED]>
Subject: Re: CD/DVD ROM speed - too much noise
Date: 07 Jun 2001 12:06:01 +0200
Benou <[EMAIL PROTECTED]> writes:
> So, is there any way to do the same under linux???
I can't see how this relates to c.o.l.*development*.system, but:
The answer is setcd. Setting are keep till shutdown (at least here).
Look around to find it for your unknown favourite distribution. And
please post to the right group next time.
Thomas
------------------------------
From: [EMAIL PROTECTED] (Lew Pitcher)
Subject: Re: information
Reply-To: [EMAIL PROTECTED]
Date: Thu, 07 Jun 2001 12:12:29 GMT
On Wed, 06 Jun 2001 19:30:13 -0000, garibaldi <[EMAIL PROTECTED]>
wrote:
> Hello:
>
> I�m looking for the progam of Vicent Larsen (autorun.exe)
> anybody know where can I find it?. It�s a very good pwl.crack
> progam.
And this has what to do with Linux system development?
Lew Pitcher, Information Technology Consultant, Toronto Dominion Bank Financial Group
([EMAIL PROTECTED])
(Opinions expressed are my own, not my employer's.)
------------------------------
From: Benou <[EMAIL PROTECTED]>
Subject: Re: CD/DVD ROM speed - too much noise
Date: Thu, 7 Jun 2001 14:30:20 +0200
Hi,
Thank you very much for the answer, I really searched for hours on the
internet without success.
Sorry for (cross)posting on this group if it is not the right one, you
can surely tell me which group would have been better for this message
(I find it somehow rude to say "please post elsewhere", without saying
what this "elsewhere" is).
Anyway, reading what is written on this group, I'm not sure I am more
out of the subject than many others. I was really sure this kind of
command would not exist, and my problem could only be solved by a
kernel extension or with a *system* trick like:
cat something > /dev/hd...
But thank you again
ben
PS: only a Debian package exists for setcd, else:
http://linux.dsi.internet2.edu/utils/disk-management/?N=D
Thomas Steffen wrote:
> Benou <[EMAIL PROTECTED]> writes:
>
>> So, is there any way to do the same under linux???
>
> I can't see how this relates to c.o.l.*development*.system, but:
>
> The answer is setcd. Setting are keep till shutdown (at least here).
> Look around to find it for your unknown favourite distribution. And
> please post to the right group next time.
>
> Thomas
>
------------------------------
From: Jan Pietrusky <[EMAIL PROTECTED]>
Subject: FIFO
Date: Thu, 07 Jun 2001 16:02:17 +0200
Hello
I will use a FIFO at my project. For at test, I wrote a small program to
create and write in a fifo and another to read from that. It runs. The
same code was written to my project, but the programm cannot open the
fifo and hang it up. I analyzed the problem and found the following
thing. The permission looks like different, the first one show
4 -rw-r--r-- my_fifo //The test, that runs
the other
0 prw-r--r-- my_fifo| // that dont run
Could anyone say me, what the problem is?
Thanks
Jan
--
---------------------------------------------------------------------
| Dipl.-Ing.(FH) Jan Pietrusky | Tel: +49 (0) 3677 678331 |
| Institut fuer Mikroelektronik- und | FAX: +49 (0) 3677 678338 |
| Mechatronik-Systeme | |
| Langewiesener Strasse 22, 98693 Ilmenau | |
|---------------------------------------------------------------------|
| MAIL/WWW: [EMAIL PROTECTED], http://www.imms.de/ |
---------------------------------------------------------------------
------------------------------
From: [EMAIL PROTECTED] (Christophe Dore)
Crossposted-To: comp.os.linux.development.apps
Subject: accept freezes
Date: 7 Jun 2001 07:59:34 -0700
Hi,
I have a multithreaded small http server that has the following
problem :
after a big bunch of accept (around 400,000), accept freezes.
I mean that you can telnet the server, send a line or two, but the
accept function does not returns, (so the data transfer socket is not
treated by the server). furthermore, what is strange is that when I do
"netstat" on the server side, I see the data transfer socket in
ESTABLISHED state...
It seems that the operating system has accepted the connection, but
has not provided it to the process....
Any idea of can lead to this ?
Any idea, hint, ... is welcome !! :-)
thanks
C.DORE
------------------------------
From: Kasper Dupont <[EMAIL PROTECTED]>
Subject: Re: FIFO
Date: Thu, 07 Jun 2001 15:06:52 +0000
Jan Pietrusky wrote:
>
> Hello
> I will use a FIFO at my project. For at test, I wrote a small program to
> create and write in a fifo and another to read from that. It runs. The
> same code was written to my project, but the programm cannot open the
> fifo and hang it up. I analyzed the problem and found the following
> thing. The permission looks like different, the first one show
It is very unclear what you are trying to do.
Do you try to write all your data to the pipe
before reading anything?
If a process is writing to the pipe it will
block after writing some amount of data until
somebody starts reading. (Probably 4KB)
>
> 4 -rw-r--r-- my_fifo //The test, that runs
This is not a pipe, it is a regular file. But
what does the number 4 at the begining mean?
Is this an output from ls? And exactly what
options did you use?
>
> the other
>
> 0 prw-r--r-- my_fifo| // that dont run
The p at the start of the permitions means
that this is a named pipe, the | at the end
of the name also means that this is a named
pipe. But I still don't know what the 0 means.
>
> Could anyone say me, what the problem is?
Perhaps if you tell us something more about
what you did, what happened, and what you
want to happen.
>
> Thanks
>
> Jan
> --
> ---------------------------------------------------------------------
> | Dipl.-Ing.(FH) Jan Pietrusky | Tel: +49 (0) 3677 678331 |
> | Institut fuer Mikroelektronik- und | FAX: +49 (0) 3677 678338 |
> | Mechatronik-Systeme | |
> | Langewiesener Strasse 22, 98693 Ilmenau | |
> |---------------------------------------------------------------------|
> | MAIL/WWW: [EMAIL PROTECTED], http://www.imms.de/ |
> ---------------------------------------------------------------------
--
Kasper Dupont
------------------------------
From: Jan Pietrusky <[EMAIL PROTECTED]>
Subject: Re: FIFO
Date: Thu, 07 Jun 2001 17:49:09 +0200
Hi Kaspar,
I know, it looks crazy. I try to explain, what I mean.
Two programms should communicate with a fifo. For a test I used the
example from www.linuxprogramming.de. The files include the following
lines
fifo_make.c
{
..
if ( mkfifo( "my_fifo", 0666 )
..
}
for writing to the fifo these
fifo_write.c
{
FILE *fifo_stream;
char data;
if ( (fifo_stream = fopen("my_fifo", "w")) == NULL)
..
fputc( data, fifo_stream );
if ( fclose( fifo_stream ) == EOF)
..
}
The program in one directory create a fifo that looks like a file
rw-r--r-- my_fifo
in another directory it is
prw-r--r-- my_fifo|
This should be a fifo. The same one can I create with mknod my_fifo p.
But in this directory, I cannot open the fifo and the program will be
hang up.
Jan
--
---------------------------------------------------------------------
| Dipl.-Ing.(FH) Jan Pietrusky | Tel: +49 (0) 3677 678331 |
| Institut fuer Mikroelektronik- und | FAX: +49 (0) 3677 678338 |
| Mechatronik-Systeme | |
| Langewiesener Strasse 22, 98693 Ilmenau | |
|---------------------------------------------------------------------|
| MAIL/WWW: [EMAIL PROTECTED], http://www.imms.de/ |
---------------------------------------------------------------------
------------------------------
From: Kasper Dupont <[EMAIL PROTECTED]>
Subject: Re: FIFO
Date: Thu, 07 Jun 2001 16:10:03 +0000
Jan Pietrusky wrote:
>
> Hi Kaspar,
> I know, it looks crazy. I try to explain, what I mean.
> Two programms should communicate with a fifo. For a test I used the
> example from www.linuxprogramming.de. The files include the following
> lines
>
> fifo_make.c
> {
> ..
> if ( mkfifo( "my_fifo", 0666 )
> ..
> }
>
> for writing to the fifo these
>
> fifo_write.c
> {
> FILE *fifo_stream;
> char data;
> if ( (fifo_stream = fopen("my_fifo", "w")) == NULL)
> ..
> fputc( data, fifo_stream );
> if ( fclose( fifo_stream ) == EOF)
> ..
> }
>
> The program in one directory create a fifo that looks like a file
> rw-r--r-- my_fifo
>
> in another directory it is
> prw-r--r-- my_fifo|
> This should be a fifo. The same one can I create with mknod my_fifo p.
> But in this directory, I cannot open the fifo and the program will be
> hang up.
>
> Jan
>
> --
> ---------------------------------------------------------------------
> | Dipl.-Ing.(FH) Jan Pietrusky | Tel: +49 (0) 3677 678331 |
> | Institut fuer Mikroelektronik- und | FAX: +49 (0) 3677 678338 |
> | Mechatronik-Systeme | |
> | Langewiesener Strasse 22, 98693 Ilmenau | |
> |---------------------------------------------------------------------|
> | MAIL/WWW: [EMAIL PROTECTED], http://www.imms.de/ |
> ---------------------------------------------------------------------
First of all you say that the program behaves different
in two different directories. Perhaps the mkfifo() call
fails, what do you do in case mkfifo() returns an error.
If you just ignore the error and continue the fopen()
call will create a file with the given name.
If a file with the given name already exist mkfifo()
will fail, otherwise it might be the case that the
directory is on a filesystem that doesn't support named
pipes.
If you try to write some data and first read it after
writing all of it a fifo will not work but a file will.
If you try to write and read data at the same time in
two different processes a fifo will work but a file
will not.
Do you run the writing and the reading program at the
same time? If both programs seems to be hanging either
try to see what the WCHAN field says. (You can see that
with ps or top.) And also try to strace the processes
with "strace -p <pid>".
--
Kasper Dupont
------------------------------
From: =?iso-8859-1?Q?Andr=E9?= David <[EMAIL PROTECTED]>
Subject: Re: information
Date: Thu, 07 Jun 2001 18:03:20 +0200
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Lew Pitcher wrote:
>
> On Wed, 06 Jun 2001 19:30:13 -0000, garibaldi <[EMAIL PROTECTED]>
> wrote:
>
> > I�m looking for the progam of Vicent Larsen (autorun.exe)
> > anybody know where can I find it?. It�s a very good pwl.crack
> > progam.
>
> And this has what to do with Linux system development?
As if Linux programmers would waste time cracking NT ... tsc tsc
;)
Andre
--
"Share the code. If you hide it ain't good."
Popular knowledge
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------------------------------
From: [EMAIL PROTECTED] (M.)
Subject: Re: mmap+/dev/zero+madvise(WILLNEED) fails?
Date: 7 Jun 2001 09:21:40 -0700
[EMAIL PROTECTED] (Zeljko Vrba) wrote in message
> /dev/zero has no secondary storage.. What exactly are you trying to accomplish?
> You should probably look into mlock.
It seems you have to be root to use mlock, and that is now always
possible.
I want to be able to allocate pages from the OS and advise the OS of
which pages to keep in memory and which pages to discard
(MADV_DONTNEED).
The usual of convention of doing this on Solaris is to open /dev/zero,
mmap it to a virtual address and then use madvise to advise the OS of
which pages to keep in core and which to move to secondary storage.
This works perfect on Solaris. However, on Linux, it doesn't seem to
like mmaping /dev/zero and then advising the OS of which pages to keep
in memory. However, madvising of DONTNEED works on linux!
M.
------------------------------
From: [EMAIL PROTECTED] (Zeljko Vrba)
Subject: Re: mmap+/dev/zero+madvise(WILLNEED) fails?
Date: 7 Jun 2001 16:49:35 GMT
Reply-To: [EMAIL PROTECTED]
On 7 Jun 2001 09:21:40 -0700, M. <[EMAIL PROTECTED]> wrote:
>
> The usual of convention of doing this on Solaris is to open /dev/zero,
> mmap it to a virtual address and then use madvise to advise the OS of
> which pages to keep in core and which to move to secondary storage.
>
What you describe is equvalent to mlock().. and mlock() needs your process
to be root because it is dangerous to lock a lot of pages in memory (a
single user could then bring down the whole system).
> This works perfect on Solaris. However, on Linux, it doesn't seem to
>
It seems to work :) You completely misunderstood the semantics of madvise.
>From the Solaris manpage about the WILNEED option:
Tells the system that a certain address range is
definitely needed so the kernel will start reading the
specified range into memory. This can benefit programs
wanting to minimize the time needed to access memory
the first time, as the kernel would need to read in
from the file.
Notice how there is no mention of keeping those pages in memory?
So the only thing WILLNEED does is to prefetch the data from secondary
storage into memory. Since there is no secondary storage associated with
/dev/zero there is nothing to prefetch and error return is perfectly logical
on Linux (EIO).. I guess Solaris is less fussy and interprets your request
another way: there is no storage, so nothing has to be done and no error can
happen..
> like mmaping /dev/zero and then advising the OS of which pages to keep
> in memory. However, madvising of DONTNEED works on linux!
>
So setuid your program to root and drop your privileges when you lock into
memory the pages you need. BTW, why would you want to lock some pages in
memory? Performance can't be the reason..
------------------------------
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End of Linux-Development-System Digest
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