I currently have three of the The Lattice Project 3.11 GB workunits
running on my Windows 7 desktop with 16 GB RAM and BOINC allowed to use
80% of it.
On the other hand, my Windows Vista desktop with 8 GB RAM and BOINC
allowed to use 40% of it has not been able to
complete such a The Lattice Project workunit successfully for months.
Allowing BOINC to use a larger fraction of the memory almost stops the
execution of any programs that use the keyboard. The 3.11 GB workunits
just cannot get enough
memory to run properly while a few 32-bit workunits are running, often
one from Rosetta@Home that uses around 500 MB, not counting any SYSWOW64
modules.
A few other differences noticed: The SYSWOW64 modules for Windows 7
(shown as svchost.exe in the Windows Task Manager if Show processes for
all users is enabled) are only a fraction of the size of those for
Windows Vista, which suggests that Windows 7 has them broken into
smaller pieces so that it does not need to load as much into memory when
only a fraction of each Windows Vista SYSWOW64 modules are used.
In other words, there is less need for separate limits for 32-bit memory
space and 64-bit memory space under Windows 7 than under Windows Vista,
because Windows 7 is more memory-efficient at running 32-bit programs.
Looks like a good reason to install Windows 7 on the 8 GB desktop AFTER
I'm no longer running any programs that aren't Windows 7 compatible.
Perhaps a way to tell the BOINC client to request ONLY 64-bit workunits,
or ONLY 32-bit workunits, would be a good temporary workaround for this
problem?
Date: Sun, 14 Apr 2013 20:17:03 -0500
From: Robert Miles <[email protected]>
Subject: Re: [boinc_dev] A problem with memory used calculations, at
least for 64-bit Windows Vista
Not the main point I was discussing. I was writing mostly about HOW MUCH
is loaded into memory, not where it is loaded. 32-bit workunits under
64-bit
Windows just won't run without any SYSWOW64 modules in memory, and
usually need about as much memory for the SYSWOW64 modules they use as
for the 32-bit application program.
-----Reply To -----
Date: Fri, 12 Apr 2013 16:37:48 +0000
From: "McLeod, John" <[email protected]>
To: Robert Miles <[email protected]>,
"[email protected]" <[email protected]>
Subject: Re: [boinc_dev] A problem with memory used calculations, at
least for 64-bit Windows Vista
Where things are loaded in memory should have no effect on reloading after a
checkpoint. No application should ever store a memory pointer into a file. If
they do, then there is a problem with the checkpointing of that application.
-----Original Message-----
From: boinc_dev [mailto:[email protected]] On Behalf Of Robert
Miles
Sent: Friday, April 12, 2013 11:56 AM
To: [email protected]
Subject: [boinc_dev] A problem with memory used calculations, at least for
64-bit Windows Vista
I've noticed the BOINC has a problem with memory used calculations under
64-bit Windows, when running a mix of 32-bit workunits and 64-bit
workunits. It does not include the SYSWOW64 modules in use by the
32-bit workunits (possibly because they are listed as being run by
System and are not in the 32-bit memory space).
These SYSWOW64 modules roughly double the amount of 64-bit memory space
needed to run these 32-bit workunits.
As a result, a 64-bit workunit can check the memory available, decide
that it's enough, and start running. However, if the total RAM is 8 GB
or less, the doubling of space occupied by 32-bit workunits can exhaust
the free memory available in 64-bit memory space before the 64-bit
workunit reaches its first checkpoint, which puts the 64-bit workunit
into Waiting to run state and can also push it into virtual memory. If
Windows does not restore it to the same addresses in 64-bit memory when
restoring it from virtual memory (I believe I've read that it does not)
and the application is not sufficiently location-independent, BOINC will
restart this workunit from the beginning, and probably encounter the
same problem again, over and over.
Seen with:
64-bit Windows Vista Home Premium SP2 (some of the programs I run aren't
compatible with later Windows versions)
8 GB RAM, but BOINC limited to using 40% of it to avoid drastic
slowdowns of non-BOINC 32-bit programs, including one of the programs in
the path for accepting keyboard input; motherboard will not hold any
more RAM
BOINC 7.0.28, but also seen with some earlier 7.0.* versions; haven't
tried any versions after 7.0.28
A The Lattice Project workunit trying to use about 3.1 GB of 64-bit
memory, but also 32-bit workunits from other projects trying to use
about 300 MB of 32-bit memory (not counting the SYSWOW64 modules)
A possible fix I've thought of: Modify BOINC to use separate memory
limits for 64-bit memory space and for 32-bit memory space. Count the
32-bit workunits, but not the SYSWOW64 modules they use, against the
limit on 32-bit memory space. Count the 64-bit workunits, the 32-bit
workunits, and the SYSWOW64 modules used by the 32-bit workunits,
against the limit on 64-bit memory space.
I've seen nothing indicating whether 64-bit versions of Windows other
than Vista also need this fix, and nothing indicating whether 64-bit
operating systems other than Windows need it.
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