Probably, but finding a name for the cause of the problem offers
little help in fixing it.
---- Robert
-----Original Message-----Date: Mon, 26 Oct 2015 14:56:54 +0000
From: Rom Walton <[email protected]>
To: Robert Miles <[email protected]>,
Subject: Re: [boinc_dev] Problems with cached memory under 64-bit
Windows
I believe you are running into SuperFetch.
See:
http://www.osnews.com/story/21471/SuperFetch_How_it_Works_Myths
----- Rom
-----Original Message-----
From: boinc_dev [mailto:[email protected]] On Behalf Of
Robert Miles
Sent: Monday, October 26, 2015 10:51 AM
To: [email protected]
Subject: [boinc_dev] Problems with cached memory under 64-bit Windows
BOINC appears to have a problem with filling the cached memory in a way
that prevents Windows from using that cached memory for any 32-bit
programs until the next restart or reboot. Problem seen under 64-bit
Windows Vista and 64-bit Windows 7; 64-bit Windows 10 appears to have a
similar problem even if it does not call anything cached memory; I do
not have any running other versions of Windows to check.
64-bit workunits appear to be able to get cached memory freed if they
need it. I do not run 64-bit programs from the console often enough to
tell if such 64-bit console programs can also free cached memory or not.
One of my computers with 8 GB of memory and 64-bit Windows Vista is now
often unable to start its email program unless I have shut down BOINC.
Another computer, with 16 GB memory and Windows 10, does not have as
obvious a problem yet, but the email program is often slow to start or
run there.
Suspending BOINC to free CPU use does not help.
My Windows Vista computer currently has 5319 of its 8190 blocks of
physical memory labelled as cached, and is slow to respond when I start
a 32-bit program with significant use of memory.
Still, the help files do not appear to explain what cached memory is,
whether it is useful to reduce the amount of cached memory, and if so,
how to do this.
So many files on the hard drives that defragmentation, full virus scans,
and other operations on all the files take 3 to 5 days, even with
nothing else running. These are mostly message files from using Windows
Mail and Windows Live Mail to read newsgroups, and save most of the
messages read or even downloaded but not yet read. This is so long that
I seldom run any operations that require reading all the files. Quick
virus scans find nothing of interest, though.
The motherboard appears to be at the maximum amount of physical memory
it can handle.
Could several of you join me in asking Microsoft to add an explanation
of whether it is useful to reduce the amount of memory cached, and if
so, how to reduce the cached memory? I'd like for them to provide a
program to show more about what is being cached, including any file
names, so that users can look harder at the files cached most often.
For example, I'd like to check if files that a program used months ago
but but not more recently are getting stored in the cache every time
that program runs.
I've found information on what memory caches are supposed to be used for
(faster access to items likely to be used again), but it looks like
BOINC does not allow enough of the cached memory to be freed when 32-bit
programs need more memory.
One idea of how to change BOINC to reduce the number of BOINC-related
files in cached memory: BOINC already has a feature for allowing
frequently used files to be stored in project directories so they can be
saved for any future workunits that need them. A new feature could be
added to allow BOINC servers to tell BOINC clients that some of the
files in the project directories are not expected to be used again, and
therefore should be deleted from the project directories so that they
cannot be loaded into cached memory in the future.
This may need some thought about what to do if a project mistakenly
lists a file as no longer needed, but some later workunit tries to use
it anyway.
Note that both the server and the client will need to have sufficiently
recent software for this new feature will work, so it should be designed
in a way that will allow older BOINC software to ignore it if only one
end of the connection supports the feature.
I have not found a definite way to duplicate this problem, but the
following method seems likely: Start with a computer with 8 GB of
memory or less, and running 64-bit Windows. Install a recent version of
BOINC, if it isn't already installed. Connect it to each of the
following BOINC projects, and run each of their applications at least once:
World Community Grid
rosetta@home
ralph@home
PrimeGrid
Milkyway@Home
GPUGRID
FiND@Home
Einstein@Home
Albert@Home
These projects were the ones that use the most disk space on my
computers, and therefore probably have the most space used in their
project directories.
My computers are connected to enough other projects to have about 20
projects in all connected.
Now, with all but one of the CPU cores running 32-bit CPU workunits, and
a GPU workunit also running, start trying to start some 32-bit program
that uses a lot of memory.
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