During some lock debugging on a dual-core Linux system I noticed that threads are blocked acquiring `cs_vNodes` and `cs_main` for long periods when the system is under moderate load from unrelated processes -- the unlucky lock acquirer is waiting for single-digit seconds once every 10 minutes or so (not coinciding with new blocks) up to around a 30 second wait every few hours. It looks like `ThreadMessageHandler` is taking locks and then due to being set to `THREAD_PRIORITY_BELOW_NORMAL`, it's being descheduled (even in trivial lock-holding regions like `GetHeight`) and holding up for arbitrarily long periods other threads that use these core locks.

So I'm wondering, what are the benefits of running the message handler at low priority?

{
    return AddLocal(CService(addr, GetListenPort()), nScore);
}
bool RemoveLocal(const CService& addr)
{
    LOCK(cs_mapLocalHost);
    LogPrintf("RemoveLocal(%s)\n", addr.ToString());
    mapLocalHost.erase(addr);
    return true;
}
void SetLimited(enum Network net, bool fLimited)
{
    if (net == NET_UNROUTABLE)
        return;
    LOCK(cs_mapLocalHost);
    vfLimited[net] = fLimited;
}
bool IsLimited(enum Network net)