This explanation actually shows me the source of this serious jank (I hope I
am using the term in the right context) I am having all of the time.I am
getting back to Chrome after a few minutes of dealing with some other
application and I have to wait, sometimes even for twenty seconds or more,
until I get the control back on the tab contents.
Sometimes I am not using a tab for a few minutes (or more) and when I switch
back to it, it takes it twenty seconds or more until I get the control back
of the tab contents.
:(
☆PhistucK
On Mon, Jun 22, 2009 at 19:57, Mike Belshe <mbel...@google.com> wrote:
>
>
> On Mon, Jun 22, 2009 at 9:29 AM, Mike Beltzner <beltz...@mozilla.com>wrote:
>
>> On 21-Jun-09, at 10:22 AM, Mike Belshe wrote:
>>
>> Second, the author is basically right. Since he's running on Vista, its
>>> a bit hard to tell whether his stats included shared memory or not; using
>>> the default memory statistic ("Memory (Private Working Set)") is actually a
>>> pretty good measure to just sum. But he doesn't say which measurement he
>>> used.
>>>
>>
>> Doesn't Private Bytes accurately represent the private memory for a given
>> process? I thought the whole point of that was that it didn't measure any
>> shared memory pools.
>
>
> Yes, that accurately represents the private memory for a process, but it
> doesn't reflect the user's experience. Windows generally tracks working
> set. Why? Because the working set is the amount of memory *not available
> to other apps*. If other apps can have the memory, then using the bytes is
> inconsequential.
>
> For most applications, there isn't much difference between private bytes
> and working set private bytes. However, because of Chrome's multi-proc
> architecture, there is a big difference. The reason is because
> Chrome intentionally gives memory back to the OS. For instance, on my
> current instance of Chrome, I'm using 16 tabs. The sum of the private bytes
> is 514408. The sum of the private working set bytes is 275040, nearly half
> of the private bytes number. This is on a machine with 8GB of RAM, so there
> is plenty of memory to go around. But if some other app wants the memory,
> Chrome gave it back to the OS and will suffer the page faults to get it
> back. Since Chrome has given it back to the OS (and has volunteered to take
> the performance consequences of getting it back), I don't think it should be
> counted as Chrome usage. Others may disagree. But Windows uses working set
> as the primary metric for all applications the OS folks agree that working
> set is the right way to account for memory usage.
>
> Single process browsers have a hard time giving memory back, because they
> can't differentiate which pages are accounted to unused, background tabs and
> which pages are accounted to the active, in-use tabs.
>
> Finally, the common metric which definitely doesn't work well is Windows
> XP's default metric: working set (private + shared). Because of shared
> memory between processes, simply summing the working set will far overstate
> the actual RAM used. Part of the motivation with Vista changing the default
> metric from working set to private working set was precisely to deal with
> the issue of better accounting of shared memory.
>
> Mike
>
>
>
> >
>
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