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From: vallor <vallor@cultnix.org>
Newsgroups: comp.os.linux.misc
Subject: Re: Are We Back to the "Wars" Now ?
Date: 22 Nov 2024 07:02:47 GMT
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On Fri, 22 Nov 2024 06:37:06 -0000 (UTC), Lawrence D'Oliveiro
<ldo@nz.invalid> wrote in <vhp8qi$12m83$2@dont-email.me>:

> On 22 Nov 2024 06:09:05 GMT, vallor wrote:
> 
>> Doesn't the named pipe connection work through the filesystem code? That
>> could add overhead.
> 
> No. The only thing that exists in the filesystem is the “special file” 
> entry in the directory. Opening that triggers special-case processing in 
> the kernel that creates the usual pipe buffering/synchronization 
> structures (or links up with existing structures created by some prior 
> opening of the same special file, perhaps by a different process), not 
> dependent on any filesystem.
> 
> I just tried creating a C program to do speed tests on data transfers 
> through pipes and socket pairs between processes. I am currently setting 
> the counter to 10 gigabytes, and transferring that amount of data (using 
> whichever mechanism) only takes a couple of seconds on my system.
> 
> So the idea that pipes are somehow not suited to large data transfers is 
> patently nonsense.
> 
>> Can't use named pipes on just any filesystem -- won't work on NFS for
>> example, unless I'm mistaken.
> 
> Hard to believe NFS could stuff that up, but there you go ...

Just tested NFS, and named pipes work there.

$ time -p ( dd if=/dev/zero of=test count=$[1024*1024] ) & cat test > /dev/null
[1] 38859
1048576+0 records in
1048576+0 records out
536870912 bytes (537 MB, 512 MiB) copied, 0.918945 s, 584 MB/s
real 0.92
user 0.16
sys 0.76

NFS vers 4.1.

-- 
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