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?

_pnode(other._pnode)
    {
        LOCK(cs_vNodes);
        _pnode->AddRef();
    }
private:
    CNode *_pnode;
};
static bool ReverseCompareNodeMinPingTime(const CNodeRef &a, const CNodeRef &b)
{
    return a->nMinPingUsecTime > b->nMinPingUsecTime;
}
static bool ReverseCompareNodeTimeConnected(const CNodeRef &a, const CNodeRef &b)
{
    return a->nTimeConnected > b->nTimeConnected;
}
class CompareNetGroupKeyed
{
    std::vector<unsigned char> vchSecretKey;
public:
    CompareNetGroupKeyed()