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authorDavid Kalnischkies <david@kalnischkies.de>2016-04-06 12:50:26 +0200
committerDavid Kalnischkies <david@kalnischkies.de>2016-04-25 15:35:52 +0200
commit4aa6ebf6d78131416ef173b1ce472f014da25136 (patch)
treea75f193e455d73754c593b9f74c990a126da2e86 /apt-pkg
parent4ad57118a8a0225b413de96dedc085e0594726a6 (diff)
make random acquire queues work less random
Queues feeding workers like rred are created in a random pattern to get a few of them to run in parallel – but if we already have an idling queue we don't need to assign it to a (potentially new) random queue as that saves us the (agruably small) overhead of starting up a new queue, avoids adding jobs to an already busy queue while others idle and as a bonus reduces the size of debug logs a bit. We also keep starting new queues now until we reach our limit before we assign work at random to them, which should give us a more effective utilisation overall compared to potentially adding work to busy queues while we haven't reached our queue limit yet.
Diffstat (limited to 'apt-pkg')
-rw-r--r--apt-pkg/acquire.cc30
1 files changed, 22 insertions, 8 deletions
diff --git a/apt-pkg/acquire.cc b/apt-pkg/acquire.cc
index 757fab057..c65aef329 100644
--- a/apt-pkg/acquire.cc
+++ b/apt-pkg/acquire.cc
@@ -352,23 +352,37 @@ string pkgAcquire::QueueName(string Uri,MethodConfig const *&Config)
return U.Access;
string AccessSchema = U.Access + ':';
- string FullQueueName;
+ string FullQueueName;
if (U.Host.empty())
{
- long randomQueue = random();
+ long existing = 0;
+ // check how many queues exist already and reuse empty ones
+ for (Queue const *I = Queues; I != 0; I = I->Next)
+ if (I->Name.compare(0, AccessSchema.length(), AccessSchema) == 0)
+ {
+ if (I->Items == nullptr)
+ return I->Name;
+ ++existing;
+ }
+
#ifdef _SC_NPROCESSORS_ONLN
long cpuCount = sysconf(_SC_NPROCESSORS_ONLN) * 2;
#else
- long cpuCount = _config->FindI("Acquire::QueueHost::Limit",10);
+ long cpuCount = 10;
#endif
- if (cpuCount > 0)
- randomQueue %= cpuCount;
+ cpuCount = _config->FindI("Acquire::QueueHost::Limit", cpuCount);
- strprintf(FullQueueName, "%s%ld", AccessSchema.c_str(), randomQueue);
- if (Debug) {
- clog << "Chose random queue " << FullQueueName << " for " << Uri << endl;
+ if (cpuCount <= 0 || existing < cpuCount)
+ strprintf(FullQueueName, "%s%ld", AccessSchema.c_str(), existing);
+ else
+ {
+ long const randomQueue = random() % cpuCount;
+ strprintf(FullQueueName, "%s%ld", AccessSchema.c_str(), randomQueue);
}
+
+ if (Debug)
+ clog << "Chose random queue " << FullQueueName << " for " << Uri << endl;
} else
{
FullQueueName = AccessSchema + U.Host;