Only antidotal evidence. We've never done any measurements, but
when compared to not doing file writes at all from the IOC, they're
expensive.
Mike
-----Original Message-----
From: Kay-Uwe Kasemir [mailto:[email protected]]
Sent: Friday, November 15, 2002 2:32 PM
To: Zelazny, Michael S.
Subject: RE: Channel Watcher V2.0
Hello Micheal:
At 03:19 PM 11/15/2002, you wrote:
><for the IOC writing to the host,> File writes are very expensive operations.
I agree with your statement.
For the SNS, we're beginning to use a tool called 'bumpless'
where the IOC periodically writes setpoints to files.
Something that's running on the host, using ChannelAccess to monitor
the values but does the file writing on the host, sounds much better.
But I'm told: No, NFS is fine, and it's running at a lower priority
so it doesn't disturb the IOC.
I just think that writing files via NFS must be lame compared to ChannelAccess:
NFS performs round-trip requests to "open", "write", "write", "write", ..
then "close".
Do you have any measurement, any proof for "file writes are expensive"?
Thanks,
-Kay
- Replies:
- Re: Channel Watcher V2.0 Brian McAllister
- Navigate by Date:
- Prev:
RE: Channel Watcher V2.0 Zelazny, Michael S.
- Next:
Re: Channel Watcher V2.0 Brian McAllister
- Index:
1994
1995
1996
1997
1998
1999
2000
2001
<2002>
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
- Navigate by Thread:
- Prev:
RE: Channel Watcher V2.0 Zelazny, Michael S.
- Next:
Re: Channel Watcher V2.0 Brian McAllister
- Index:
1994
1995
1996
1997
1998
1999
2000
2001
<2002>
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
|