Merge lp:~hloeung/ubuntu-repository-cache/drop-max-spare-threads into lp:ubuntu-repository-cache

[Haw Loeung]

Drop MaxSpareThreads - LP:1918211

We can't have too many around to allow for a server process to cycle
out. Otherwise we're back at the issue with scoreboard is full, not at
MaxRequestWorkers.

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

[Paul Collins (pjdc)]

Doesn't this make for fewer spare threads? (As the test-case updates seem to imply.)

I'd be interested to wait and see if the extra process is enough by itself.

Right now I would expect that as process A is gracefulling and marking its scoreboard entries as unusable, process B will take requests and spawn more threads if needed up to MaxSpareThreads.

[Haw Loeung (hloeung)]

> Doesn't this make for fewer spare threads? (As the test-case updates seem to
> imply.)

It makes it back to the no. of spare threads before the change to add an additional server process (ServerLimit 2 rather than 1). We still keep a bunch of spare threads, enough or max. for a single process.

> I'd be interested to wait and see if the extra process is enough by itself.
>
> Right now I would expect that as process A is gracefulling and marking its
> scoreboard entries as unusable, process B will take requests and spawn more
> threads if needed up to MaxSpareThreads.

Sure, marking this as WIP for the moment so we can see how the extra process is doing.

[Haw Loeung (hloeung)]

> > Doesn't this make for fewer spare threads? (As the test-case updates seem to
> > imply.)
>
> It makes it back to the no. of spare threads before the change to add an
> additional server process (ServerLimit 2 rather than 1). We still keep a bunch
> of spare threads, enough or max. for a single process.

That's from https://code.launchpad.net/~hloeung/ubuntu-repository-cache/extra-server-process/+merge/399536

[Paul Collins (pjdc)]

> > > Doesn't this make for fewer spare threads? (As the test-case updates seem
> to
> > > imply.)
> >
> > It makes it back to the no. of spare threads before the change to add an
> > additional server process (ServerLimit 2 rather than 1). We still keep a
> bunch
> > of spare threads, enough or max. for a single process.
>
> That's from https://code.launchpad.net/~hloeung/ubuntu-repository-cache/extra-
> server-process/+merge/399536

Ah, I see. Thanks!

[Haw Loeung (hloeung)]

Not needed now.

Unmerged revisions

333. By Haw Loeung on 2021-03-12

Drop MaxSpareThreads - LP:1918211

We can't have too many around to allow for a server process to cycle
out. Otherwise we're back at the issue with scoreboard is full, not at
MaxRequestWorkers.

=== modified file 'lib/ubuntu_repository_cache/apache.py'
--- lib/ubuntu_repository_cache/apache.py	2021-03-11 23:09:11 +0000
+++ lib/ubuntu_repository_cache/apache.py	2021-03-12 03:05:02 +0000
@@ -122,7 +122,7 @@
         config['minsparethreads'] = int(config['maxrequestworkers'] * 0.5)
 
     if not config['maxsparethreads']:
-        config['maxsparethreads'] = config['maxrequestworkers']
+        config['maxsparethreads'] = config['minsparethreads']
 
     return config
 

=== modified file 'lib/ubuntu_repository_cache/tests/test_apache.py'
--- lib/ubuntu_repository_cache/tests/test_apache.py	2021-03-11 23:09:11 +0000
+++ lib/ubuntu_repository_cache/tests/test_apache.py	2021-03-12 03:05:02 +0000
@@ -39,7 +39,7 @@
         expected = {
             'startservers': 1,
             'minsparethreads': 1024,
-            'maxsparethreads': 2048,
+            'maxsparethreads': 1024,
             'threadlimit': 1024,
             'threadsperchild': 1024,
             'serverlimit': 2,
@@ -62,7 +62,7 @@
         expected = {
             'startservers': 1,
             'minsparethreads': 1280,
-            'maxsparethreads': 2560,
+            'maxsparethreads': 1280,
             'threadlimit': 1280,
             'threadsperchild': 1280,
             'serverlimit': 2,
@@ -85,7 +85,7 @@
         expected = {
             'startservers': 1,
             'minsparethreads': 256,
-            'maxsparethreads': 512,
+            'maxsparethreads': 256,
             'threadlimit': 256,
             'threadsperchild': 256,
             'serverlimit': 2,
@@ -108,7 +108,7 @@
         expected = {
             'startservers': 1,
             'minsparethreads': 512,
-            'maxsparethreads': 1024,
+            'maxsparethreads': 512,
             'threadlimit': 512,
             'threadsperchild': 512,
             'serverlimit': 2,

=== modified file 'tests/unit/test_apache.py'
--- tests/unit/test_apache.py	2021-03-11 23:09:11 +0000
+++ tests/unit/test_apache.py	2021-03-12 03:05:02 +0000
@@ -239,7 +239,7 @@
             {
                 'maxconnectionsperchild': 10000,
                 'maxrequestworkers': 1024,
-                'maxsparethreads': 1024,
+                'maxsparethreads': 512,
                 'minsparethreads': 512,
                 'serverlimit': 2,
                 'startservers': 1,