For some time now I've been bugging Janko about the memory usage of the process that serves http://www.squeak.org/ . I've gathered a bit more info today and I'd like to see if anyone here has any thoughts.
First while there is some variation most of the Squeak processes that serve squeak.org sites (source.squeak.org, map.squeak.org, wiki.squeak.org) have a more or less constant and reasonable memory usage. Let me clarify that what I am talking about here is RSS (Resident Set Size) as reported by ps/top on Linux. Swiki as the oldest of the group is the clear winner at just under 30MB, squeakmap is around 47MB, and source.squeak.org is around 59MB.
In contrast immediately after starting it www.squeak.org is using about 70MB and it grows from there. Now a bit more than an hour since the last restart it is already up to about 85MB. I have seen it over 300MB before, and it commonly uses 140-250MB. It doesn't simply grow and grow, it does shrink occasionally.
First, there is a known issue with Swazoo that it does not close sockets correctly and Janko has addressed this by having Swazoo automatically restarted every 15 minutes. So using netstat for example I can watch the socket count for the process continually grow and then it drops to zero and this repeats. In contrast for all the other process (all running some variation of Kom/Comanche I believe) I'm hard pressed to even catch a single open socket at any time (not counting the listener that is).
Secondly, since I've been complaining about this issue for a long time Janko has running a little morph that shows current memory usage. What this shows is the values of SmalltalkImage current vmParameterAt: 2 and 3. These numbers are quite stable. For example at this moment these are 68.3MB and 71.0MB respectively. Whereas ps shows the RSS at 85752KB. Where is the discrepancy here?
My current theory is that the vmParameters are not reflecting incidental memory use by the VM and plugins or that we are simply misinterpreting the values. Is it possible that Swazoo is failing to release something that is causing the VM to use more memory than it should?
Note that the same VM is used by all of these processes. It is
3.8a-1 #1 Sun May 1 19:46:46 EDT 2005 gcc 3.3.5
Yes, I know it's old, but 'if it ain't broke, don't fix it' has been the motto and with the possible exception of Swazoo/www.squeak.org it has been working wonderfully for a long time now.
Your thoughts would be greatly appreciated,
Ken
An update as things may not be quite as I originally described them. It seems the values reported by vmParameters 2 and 3 are not as constant as I had been lead to believe. I noticed that just a short while after sending the image the RSS had jumped up to 165800KB. I still had VNC open on the image so I checked what is shown there and I see 145.6MB/147.7MB so there is still a discrepancy, but not perhaps as wide as I indicated.
I also did not mention that in addition to restarting Swazoo every 15 minutes there is other cleanup that is done once a day related to statistics gathering that goes on. My understanding is that this cleanup is meant to return things very close to the starting state. Perhaps Janko can comment on that more fully.
Ken
On Thu, 2010-10-14 at 16:55 -0500, Ken Causey wrote:
For some time now I've been bugging Janko about the memory usage of the process that serves http://www.squeak.org/ . I've gathered a bit more info today and I'd like to see if anyone here has any thoughts.
First while there is some variation most of the Squeak processes that serve squeak.org sites (source.squeak.org, map.squeak.org, wiki.squeak.org) have a more or less constant and reasonable memory usage. Let me clarify that what I am talking about here is RSS (Resident Set Size) as reported by ps/top on Linux. Swiki as the oldest of the group is the clear winner at just under 30MB, squeakmap is around 47MB, and source.squeak.org is around 59MB.
In contrast immediately after starting it www.squeak.org is using about 70MB and it grows from there. Now a bit more than an hour since the last restart it is already up to about 85MB. I have seen it over 300MB before, and it commonly uses 140-250MB. It doesn't simply grow and grow, it does shrink occasionally.
First, there is a known issue with Swazoo that it does not close sockets correctly and Janko has addressed this by having Swazoo automatically restarted every 15 minutes. So using netstat for example I can watch the socket count for the process continually grow and then it drops to zero and this repeats. In contrast for all the other process (all running some variation of Kom/Comanche I believe) I'm hard pressed to even catch a single open socket at any time (not counting the listener that is).
Secondly, since I've been complaining about this issue for a long time Janko has running a little morph that shows current memory usage. What this shows is the values of SmalltalkImage current vmParameterAt: 2 and 3. These numbers are quite stable. For example at this moment these are 68.3MB and 71.0MB respectively. Whereas ps shows the RSS at 85752KB. Where is the discrepancy here?
My current theory is that the vmParameters are not reflecting incidental memory use by the VM and plugins or that we are simply misinterpreting the values. Is it possible that Swazoo is failing to release something that is causing the VM to use more memory than it should?
Note that the same VM is used by all of these processes. It is
3.8a-1 #1 Sun May 1 19:46:46 EDT 2005 gcc 3.3.5
Yes, I know it's old, but 'if it ain't broke, don't fix it' has been the motto and with the possible exception of Swazoo/www.squeak.org it has been working wonderfully for a long time now.
Your thoughts would be greatly appreciated,
Ken
Another update with more data conflicting somewhat with my last report:
Shown by ps: 214560KB RSS Shown by vmParameters (2,3): 64.6MB/67.4MB
A discrepancy of some 150MB.
Ken
On Thu, 2010-10-14 at 17:31 -0500, Ken Causey wrote:
An update as things may not be quite as I originally described them. It seems the values reported by vmParameters 2 and 3 are not as constant as I had been lead to believe. I noticed that just a short while after sending the image the RSS had jumped up to 165800KB. I still had VNC open on the image so I checked what is shown there and I see 145.6MB/147.7MB so there is still a discrepancy, but not perhaps as wide as I indicated.
I also did not mention that in addition to restarting Swazoo every 15 minutes there is other cleanup that is done once a day related to statistics gathering that goes on. My understanding is that this cleanup is meant to return things very close to the starting state. Perhaps Janko can comment on that more fully.
Ken
On Thu, 2010-10-14 at 16:55 -0500, Ken Causey wrote:
For some time now I've been bugging Janko about the memory usage of the process that serves http://www.squeak.org/ . I've gathered a bit more info today and I'd like to see if anyone here has any thoughts.
First while there is some variation most of the Squeak processes that serve squeak.org sites (source.squeak.org, map.squeak.org, wiki.squeak.org) have a more or less constant and reasonable memory usage. Let me clarify that what I am talking about here is RSS (Resident Set Size) as reported by ps/top on Linux. Swiki as the oldest of the group is the clear winner at just under 30MB, squeakmap is around 47MB, and source.squeak.org is around 59MB.
In contrast immediately after starting it www.squeak.org is using about 70MB and it grows from there. Now a bit more than an hour since the last restart it is already up to about 85MB. I have seen it over 300MB before, and it commonly uses 140-250MB. It doesn't simply grow and grow, it does shrink occasionally.
First, there is a known issue with Swazoo that it does not close sockets correctly and Janko has addressed this by having Swazoo automatically restarted every 15 minutes. So using netstat for example I can watch the socket count for the process continually grow and then it drops to zero and this repeats. In contrast for all the other process (all running some variation of Kom/Comanche I believe) I'm hard pressed to even catch a single open socket at any time (not counting the listener that is).
Secondly, since I've been complaining about this issue for a long time Janko has running a little morph that shows current memory usage. What this shows is the values of SmalltalkImage current vmParameterAt: 2 and 3. These numbers are quite stable. For example at this moment these are 68.3MB and 71.0MB respectively. Whereas ps shows the RSS at 85752KB. Where is the discrepancy here?
My current theory is that the vmParameters are not reflecting incidental memory use by the VM and plugins or that we are simply misinterpreting the values. Is it possible that Swazoo is failing to release something that is causing the VM to use more memory than it should?
Note that the same VM is used by all of these processes. It is
3.8a-1 #1 Sun May 1 19:46:46 EDT 2005 gcc 3.3.5
Yes, I know it's old, but 'if it ain't broke, don't fix it' has been the motto and with the possible exception of Swazoo/www.squeak.org it has been working wonderfully for a long time now.
Your thoughts would be greatly appreciated,
Ken
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Ken Causey