Fw: [Bug 206919] New: Very bad performance of sendto function

Fw: [Bug 206919] New: Very bad performance of sendto function

[Stephen Hemminger]

There maybe something here but probably not.

Begin forwarded message:

Date: Sun, 22 Mar 2020 11:22:46 +0000
From: bugzilla-daemon@bugzilla.kernel.org
To: stephen@networkplumber.org
Subject: [Bug 206919] New: Very bad performance of sendto function


https://bugzilla.kernel.org/show_bug.cgi?id=206919

            Bug ID: 206919
           Summary: Very bad performance of sendto function
           Product: Networking
           Version: 2.5
    Kernel Version: 5.4.13
          Hardware: All
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: Other
          Assignee: stephen@networkplumber.org
          Reporter: bernat.arlandis@gmail.com
        Regression: No

Created attachment 288007
  --> https://bugzilla.kernel.org/attachment.cgi?id=288007&action=edit  
Sysprof capture file

Hi,

I have a case where the sendto function is slowing down the software I'm trying
to use. Sysprof capture file attached.

It's probably being called at a high frequency and the __netlink_dump_start
function spends a lot of time in the mutex lock, then also in the netlink_dump
call.

This is causing the threads calling the function to stall. At least this is my
interpretation of the profiling session.

I don't have any knowledge about the way networking code works. I'd like to
know if the flaw is in the user-space software or in the kernel. Can I provide
any more info or do some test to help determine what's happening? I'd like to
help fix it.

My NIC: Intel Corporation I211 Gigabit Network Connection (rev 03)

My system: Debian 10 with kernel 5.4.13.

Thanks.

-- 
You are receiving this mail because:
You are the assignee for the bug.

RE: [Bug 206919] New: Very bad performance of sendto function

[David Laight]

From: Stephen Hemminger
> Sent: 23 March 2020 16:59
> To: netdev@vger.kernel.org
> Subject: Fw: [Bug 206919] New: Very bad performance of sendto function
> 
> There maybe something here but probably not.

They need to raise it with wine.

They don't even say what sort of message rate they are getting
(or trying to get).

	David

> Begin forwarded message:
> 
> Date: Sun, 22 Mar 2020 11:22:46 +0000
> From: bugzilla-daemon@bugzilla.kernel.org
> To: stephen@networkplumber.org
> Subject: [Bug 206919] New: Very bad performance of sendto function
> 
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=206919
> 
>             Bug ID: 206919
>            Summary: Very bad performance of sendto function
>            Product: Networking
>            Version: 2.5
>     Kernel Version: 5.4.13
>           Hardware: All
>                 OS: Linux
>               Tree: Mainline
>             Status: NEW
>           Severity: normal
>           Priority: P1
>          Component: Other
>           Assignee: stephen@networkplumber.org
>           Reporter: bernat.arlandis@gmail.com
>         Regression: No
> 
> Created attachment 288007
>   --> https://bugzilla.kernel.org/attachment.cgi?id=288007&action=edit
> Sysprof capture file
> 
> Hi,
> 
> I have a case where the sendto function is slowing down the software I'm trying
> to use. Sysprof capture file attached.
> 
> It's probably being called at a high frequency and the __netlink_dump_start
> function spends a lot of time in the mutex lock, then also in the netlink_dump
> call.
> 
> This is causing the threads calling the function to stall. At least this is my
> interpretation of the profiling session.
> 
> I don't have any knowledge about the way networking code works. I'd like to
> know if the flaw is in the user-space software or in the kernel. Can I provide
> any more info or do some test to help determine what's happening? I'd like to
> help fix it.
> 
> My NIC: Intel Corporation I211 Gigabit Network Connection (rev 03)
> 
> My system: Debian 10 with kernel 5.4.13.
> 
> Thanks.
> 
> --
> You are receiving this mail because:
> You are the assignee for the bug.

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