how to change priority of pipe commands?

[einstein1969]

Hi,

I would like to know if there is a possibility of giving a priority to all processes involved in a pipe

Example:

Code: Select all

batch1.cmd | batch2.cmd

I wish that all the children processes involved were assigned the same priority

How can I do?

[jeb]

Hi einstein1969,

I suppose the only way to change the process priority is to use the START cmd.

There are 5 options

Code: Select all

  LOW
  NORMAL
  HIGH
  REALTIME
  ABOVENORMAL
  BELOWNORMAL

So if you want to use it with pipes you could add the start command at each side.

Code: Select all

start "" /b /LOW cmd /c batch1.cmd | start "" /b /LOW cmd /c batch2.cmd

jeb

[einstein1969]

Thanks Jeb,

I have a problem with priority abovenormal, high and realtime.

When i start with belovenormal and low this works. But when i start with higher priority some child processes have "normal" priority

example

Start.cmd:

Code: Select all

@echo off

echo [ZERO] [%time%] > CON

start "" /b /HIGH cmd /c batch1.cmd | start "" /b /HIGH cmd /c batch2.cmd

batch1.cmd:

Code: Select all

@echo off

echo [ONE] [%time%] > CON

start "" /b /HIGH cmd /c batch1_1.cmd | start "" /b /HIGH cmd /c batch1_2.cmd

batch2.cmd:

Code: Select all

@echo off

echo [TWO] [%time%] > CON

:two

set "ln="

set /p "ln="

if defined ln echo [Two] [%time%] %ln%

goto :two

batch1_1.cmd

Code: Select all

@echo off

echo [ONE_ONE] [%time%] > CON

typeperf "\Processore(_Total)\%% Tempo processore"

Rem typeperf "\Processor(_Total)\%% Processor Time"

batch1_2.cmd

Code: Select all

@echo off

echo [ONE_TWO] [%time%] > CON

more +2

When i use LOW and BELOWNORMAL the processes "more" and "typeperf" go LOW or BELOWNORMAL, but when i use priority over NORMAL these keep normal priority

I use xp sp2.

[Liviu]

So if you want to use it with pipes you could add the start command at each side.

Interesting thought, thanks for the hint. That said, there is something odd with piping between two "start" commands. The following requires an ^Z to be manually entered before the command completes.

Code: Select all

C:\tmp>start "" /b /LOW cmd /c echo 123 | start "" /b /LOW cmd /c more

123

^Z
C:\tmp>

Liviu

[Ed Dyreen]

'
Some time ago, I discover a bug in the start command of winXP causing priority changes to fail.

Just switching the order of the parameters should do it ( I hope ).

Code: Select all

start "" /high /b "cmd" /c "batch1.cmd" |start "" /high /b "cmd" /c "batch2.cmd"

[einstein1969]

So if you want to use it with pipes you could add the start command at each side.

Interesting thought, thanks for the hint. That said, there is something odd with piping between two "start" commands. The following requires an ^Z to be manually entered before the command completes.

Code: Select all

C:\tmp>start "" /b /LOW cmd /c echo 123 | start "" /b /LOW cmd /c more

123

^Z
C:\tmp>

Liviu

Yes, odd

It's more problem?

Code: Select all

C:\Documents and Settings\fra>cmd /c more


^D
♦
^A
☺
^X
↑
^B
☻
^Z


C:\Documents and Settings\fra>

[einstein1969]

'
Some time ago, I discover a bug in the start command of winXP causing priority changes to fail.

Just switching the order of the parameters should do it ( I hope ).

Code: Select all

start "" /high /b "cmd" /c "batch1.cmd" |start "" /high /b "cmd" /c "batch2.cmd"

I tried:

Code: Select all

start "" /HIGH /b "cmd" /c "batch1_1.cmd" | start "" /HIGH /b  "cmd" /c "batch1_2.cmd"

but he problem remains

[Ed Dyreen]

'
Odd, did you verify with taskManager ?, I ran
'test.CMD'

Code: Select all

@echo off

start "" /high /b "cmd" /c "1.cmd" |start "" /high /b "cmd" /c "2.cmd"

pause
exit

'1.CMD' And '2.CMD'

Code: Select all

@echo off

echo.%~n0

pause

and process '2.CMD' runs high as I expected ( did not verify priority of '1.CMD' )

[Liviu]

It's more problem?

Code: Select all

C:\Documents and Settings\fra>cmd /c more
^D
♦

I don't see the problem there. It works the same with "echo ^D", and the same with just "more" instead of "cmd /c more". The display difference between "^D" (input) and "♦" (output) is just an artifact of how the console I/O works.

The "odd" part in my previous example was the additional ^Z required when piping between "start cmd /c" commands, which is not otherwise necessary when running the commands directly e.g. "echo 123 | more".

Liviu

[Ed Dyreen]

'

The "odd" part in my previous example was the additional ^Z required when piping between "start cmd /c" commands, which is not otherwise necessary when running the commands directly e.g. "echo 123 | more".

You are piping into 'start', not into 'more'.

Code: Select all

echo.123 |start "" /b cmd /c more

it is not the same as

Code: Select all

echo.123 |more

yet translates into

Code: Select all

>more
^Z


>echo.123 |start "" /b cmd /c more

123

^Z
>

[Liviu]

You are piping into 'start', not into 'more'.

Right. My first post was in reply to jeb's clever usage of 'start'. The point I was making is that, with piped input, the 'start' behavior does not match the same command being run directly, but (sometimes?) requires an extra ^Z to close the pipe.

In more detail...

Code: Select all

C:\tmp>echo 123 | (cmd /c more)
123


C:\tmp>echo 123 | (start /b cmd /c more)

123

^Z
C:\tmp>

...the first command completes without any additional input, while the second one needs that extra ^Z. The difference is definitely with the receiving end of the pipe i.e. the 'start' part, since running the second line without "/b" opens (as expected) a separate console, and waits for a ^Z to be entered there.

Liviu

[einstein1969]

'
Odd, did you verify with taskManager ?, I ran
'test.CMD'

Code: Select all

@echo off

start "" /high /b "cmd" /c "1.cmd" |start "" /high /b "cmd" /c "2.cmd"

pause
exit

'1.CMD' And '2.CMD'

Code: Select all

@echo off

echo.%~n0

pause

and process '2.CMD' runs high as I expected ( did not verify priority of '1.CMD' )

Your example work. Process 1.cmd run at expected priority.

But if there is other process in 1.cmd or 2.cmd the priority of this process is not respect.

[einstein1969]

You are piping into 'start', not into 'more'.

Right. My first post was in reply to jeb's clever usage of 'start'. The point I was making is that, with piped input, the 'start' behavior does not match the same command being run directly, but (sometimes?) requires an extra ^Z to close the pipe.

In more detail...

Code: Select all

C:\tmp>echo 123 | (cmd /c more)
123


C:\tmp>echo 123 | (start /b cmd /c more)

123

^Z
C:\tmp>

...the first command completes without any additional input, while the second one needs that extra ^Z. The difference is definitely with the receiving end of the pipe i.e. the 'start' part, since running the second line without "/b" opens (as expected) a separate console, and waits for a ^Z to be entered there.

Liviu

may be a problem with the "real" asynchronous start?

Code: Select all

echo 123 | (start /b /wait cmd /c more)

[einstein1969]

And I caught the problem of inverted parameters...

Code: Select all

14.06.02,21> echo 123 | (start /b /wait cmd /c more)
123


14.06.07,43>

exchanging /b /wait

Code: Select all

14.06.07,43> echo 123 | (start /wait /b cmd /c more)

123

^Z
14.07.16,77>

and there is a line...

This in XP SP2