On 5/7/14, 12:36 PM, Luc R. wrote:
Thanks Benjamin. Do I understand right that the MemoryPressureHandler
is an additional mechanism to reduce memory on top of other things,
but is not the root cause of memory increase at first place?
Yes, MemoryPressureHandler is one of our tools for managing memory, not
the cause.
The way WebKit runs nowadays is: use as much memory as needed to improve
the runtime performance (while being reasonable of course). When the
system needs the memory back, MemoryPressureHandler clears the major
caches and return the memory to the system.
It is a common pattern from OS X: if there is spare memory available,
use if for runtime performance. When memory becomes scarce, the
operating system reclaim memory from the processes that do not require
high performance at this time.
An extra information on memory pattern:
For the new code, amount of committed memory is actually less for
about 2x on average (say 150M vs 300M per process), but private memory
is higher say 100M vs 60M per process, as well as is the working set.
The scenario is a continuous processing a URL list until process
crashing. My interpretation that somehow processes burn more physical
memory, instead of letting it page out to disk. Does it make sense?
This looks like a dramatic change. Are there any major changes in
memory management in the last 2 years? Are there any sensitive
settings which can be tuned up?
WebKit is an extremely active project, there are several hundred changes
every day. Some subsystems have been entirely rewritten in the last two
years. Without more information about which subsystem uses more memory,
it is impossible for me to guess what is happening.
Regarding the settings, you should at least disable the page cache since
it should be useless for your use case.
If you send the list of objects that are taking more memory, I may be
able to give more information.
Benjamin
On Mon, May 5, 2014 at 6:38 PM, Benjamin Poulain <benja...@webkit.org
<mailto:benja...@webkit.org>> wrote:
On 5/5/14, 6:31 PM, Luc R. wrote:
Question on memory usage.
I am using WinCairo port, and I have recently updated the
codebase from
about 2 years old one. I am running an automation with multiple
instances of WebKit running in parallel, and each instance is
processing
a list of URLs (until crashes, then it's restarted).
I noticed that memory usage on the new codebase is about 60%
higher! I
don't see substantial differences in the output (which is
pretty much
outerHTML) and processing speed is about the same.
Does anyone have ideas, which feature could have added such a
significant increase of memory usage? I would be interested to
look into
details of how to reduce that back to normal.
WebKit is becoming a lot better at using memory efficiently to
improve the runtime performance. It could simply be better use of
the ram.
You should try to wiring the MemoryPressureHandler with your
system, and see if that makes a difference.
Benjamin
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-Luc
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