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?

{
    LOCK(cs_vNodes);
    BOOST_FOREACH(CNode* pnode, vNodes)
    if (subNet.Match((CNetAddr)pnode->addr))
        return (pnode);
    return NULL;
}
CNode* FindNode(const std::string& addrName)
{
    LOCK(cs_vNodes);
    BOOST_FOREACH(CNode* pnode, vNodes)
        if (pnode->addrName == addrName)
            return (pnode);
    return NULL;
}
CNode* FindNode(const CService& addr)
{
    LOCK(cs_vNodes);
    BOOST_FOREACH(CNode* pnode, vNodes)
        if ((CService)pnode->addr == addr)
            return (pnode);
    return NULL;
}
CNode* ConnectNode(CAddress addrConnect, const char *pszDest)