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_mapLocalHost);
    return !vfLimited[net];
}
bool IsReachable(const CNetAddr& addr)
{
    enum Network net = addr.GetNetwork();
    return IsReachable(net);
}
void AddressCurrentlyConnected(const CService& addr)
{
    addrman.Connected(addr);
}
uint64_t CNode::nTotalBytesRecv = 0;
uint64_t CNode::nTotalBytesSent = 0;
CCriticalSection CNode::cs_totalBytesRecv;
CCriticalSection CNode::cs_totalBytesSent;
uint64_t CNode::nMaxOutboundLimit = 0;
uint64_t CNode::nMaxOutboundTotalBytesSentInCycle = 0;
uint64_t CNode::nMaxOutboundTimeframe = 60*60*24; 
uint64_t CNode::nMaxOutboundCycleStartTime = 0;
CNode* FindNode(const CNetAddr& ip)
{
    LOCK(cs_vNodes);
    BOOST_FOREACH(CNode* pnode, vNodes)
        if ((CNetAddr)pnode->addr == ip)
            return (pnode);
    return NULL;
}
CNode* FindNode(const CSubNet& subNet)