Correction to my earlier claims about our minimum memory requirement.
The stub installer will default to 64-bit for users with >= 1800 MB. So
users with exactly 2 GB should get 64-bit Firefox. Only Win64 users with
strictly less than 2 GB will default to 32-bit Firefox.
Why the magic number 1800 MB? The Windows API we use to query the
machine's available memory omits physical memory reserved for hardware
drivers, which is typically a couple hundred KB. So most "2 GB" machines
will report less than 2048 MB available memory.
Stub installer's memory check:
https://searchfox.org/mozilla-central/source/browser/installer/windows/nsis/stub.nsi#189-195
On 2017-08-07 1:19 AM, Nicholas Nethercote wrote:
I think the 2GB "requirement" from Microsoft should be ignored,
because plenty of our users are ignoring it.
Nick
On Mon, Aug 7, 2017 at 5:51 PM, Chris Peterson <cpeter...@mozilla.com
<mailto:cpeter...@mozilla.com>> wrote:
On 2017-08-06 11:26 PM, Henri Sivonen wrote:
On Thu, Jul 20, 2017 at 10:42 AM, Chris
Peterson<cpeter...@mozilla.com <mailto:cpeter...@mozilla.com>>
wrote:
Users with only 2 GB and 5 minute browser sessions would
probably have a
faster user experience with 32-bit Firefox than with
64-bit, but how do we
weigh that experience versus the security benefits of ASLR?
Not giving users a security mechanism due to a non-obvious reason
feels bad. Furthermore, considering that Microsoft documents 2
GB as a
"requirement" for 64-bit Windows, is it really worthwhile for
us to
treat three Windows pointer size combinations (32-bit on 32-bit,
64-bit on 64-bit and 32-bit on 64-bit) as fully supported when
one of
the combinations is in contradiction with the OS vendor's stated
requirements?
Do we have any metrics on whether 32-bit on 64-bit exhibits
bugs that
32-bit on 32-bit and 64-bit on 64-bit don't? That is, what
kind of bug
burden are we keeping by catering to users who've installed 64-bit
Windows with less than 2 GB of RAM in contradiction with what
Microsoft states as a requirement?
That's a fair question. 32-bit applications can only access 2 GB
of virtual address space on Win32 OS, but can access 4 GB on Win64
OS. So in theory, some 32-bit pointer bugs could manifest
differently on Win64 and Win32.
Do we test 32-bit Firefox on Win32 or Win64 today? I know we build
32-bit Firefox on Win64. Since more people will run 32-bit Firefox
on Win32 than on Win64, we should probably test on Win32 or at
least test on Win64 configured to only allow Firefox access to 2
GB of virtual address space.
In our experiments with Win64 OS users, users with 2 GB or less
had slightly worse retention and crash rates when running 64-bit
Firefox than 32-bit Firefox.
About 8% of Win64 users in our experiment had 2 GB or less, so we
are talking about choosing a worse user experience for a fair
number of people. (We didn't break out how many users had strictly
less than 2 GB.) 64-bit Chrome's minimum memory requirement is 4
GB, so Google has similarly decided that supporting 32-bit on
Win64 is worth the trouble.
_______________________________________________
dev-platform mailing list
dev-platform@lists.mozilla.org <mailto:dev-platform@lists.mozilla.org>
https://lists.mozilla.org/listinfo/dev-platform
<https://lists.mozilla.org/listinfo/dev-platform>
_______________________________________________
dev-platform mailing list
dev-platform@lists.mozilla.org
https://lists.mozilla.org/listinfo/dev-platform
