[Box-Admins] [Vm-dev] Could someone add a VMMaker Inbox project to source.squeak.org?
bert at freudenbergs.de
Tue Oct 2 23:22:36 UTC 2018
[Let's move that part of the discussion here]
Our virtual server might be significantly slower than your machine. But it
still seems suspiciously slow, agreed.
- Bert -
On Tue, Oct 2, 2018 at 3:54 PM Levente Uzonyi <leves at caesar.elte.hu> wrote:
> On Tue, 2 Oct 2018, Chris Muller wrote:
> > There are a number of factors that combine to lead to occasional
> > timeouts depending on the package.
> > In this case, VMMaker is a huge package, and it takes a long time for
> > the server to open up the .mcz and materialize its contents. That's
> > why, for example, the diffing operation, which doesn't use Magma at
> > all, times out.
> I measured diff creation on my machine using various VMMaker versions:
> - creating a diff of 2 versions takes less than 2 seconds
> - from this 2 seconds the actuall diff creation takes about 150ms, which
> can easily be halved with some basic optimizations
> - more than a second is spent by DataStream reading and mangling strings
> for no real reason. We should be able to significantly reduce that as
> - the remaining few hundred milliseconds is spent on parsing the ancestry,
> which can only be solved by using a new non-recursive ancestry format
> which doesn't require you to parse everything to read a single entry.
> But 2 seconds is not enough to get a 504 response, so there must be some
> other reason for those timeouts.
> > When a new version of VMMaker is saved, once again, it must be opened
> > up by the server and then, all of its MCDefinitions are enumerated and
> > indexed into huge Dictionary's stored by Magma. This takes a long
> > time and even though it occurs in a background local Smalltalk
> > Process, it can affect local image performance.
> > Another cause are the many thousands of files which the server must
> > constantly refresh its directory cache, again and again, as it grows
> > ever larger.
> > Yet another issue is the dual persistence -- currently since we use
> > both File-based AND Magma, we have to save a "data.obj" file, and so
> > we're forced to keep the entire model into memory instead of taking
> > advantage of Magma's ability to work efficiently with subgraphs of
> > models. But this is the only way we can have the MC history and
> > origin functions.
> > As I run the exact same code repository on my laptops to manage my own
> > code as runs source.squeak.org, after Squeak 5.2, I plan to refresh
> > and test my own codebase, bring it up to 64-bit, latest Magma, and
> > make some optimizations. I'll test it by running my own development
> > with it for a while and then apply the same upgrades to
> > source.squeak.org.
> > - Chris
> > On Tue, Oct 2, 2018 at 12:08 PM Levente Uzonyi <leves at caesar.elte.hu>
> >> My impression is that these slowdowns are present since the update to
> >> Magma backend.
> >> I haven't seen the code yet, but I presume the code accessing data from
> >> Magma is responsible for this, and someone familiar with Magma can
> >> fix it.
> >> Levente
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