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?

#include <math.h>
#define DUMP_ADDRESSES_INTERVAL 900
#if !defined(HAVE_MSG_NOSIGNAL) && !defined(MSG_NOSIGNAL)
#define MSG_NOSIGNAL 0
#endif
#ifdef WIN32
#ifndef PROTECTION_LEVEL_UNRESTRICTED
#define PROTECTION_LEVEL_UNRESTRICTED 10
#endif
#ifndef IPV6_PROTECTION_LEVEL
#define IPV6_PROTECTION_LEVEL 23
#endif
#endif
using namespace std;
namespace {
    const int MAX_OUTBOUND_CONNECTIONS = 8;
    struct ListenSocket {
        SOCKET socket;
        bool whitelisted;
        ListenSocket(SOCKET socket, bool whitelisted) : socket(socket), whitelisted(whitelisted) {}
    };
}
const static std::string NET_MESSAGE_COMMAND_OTHER = "*other*";
bool fDiscover = true;
bool fListen = true;
uint64_t nLocalServices = NODE_NETWORK;
CCriticalSection cs_mapLocalHost;
map<CNetAddr, LocalServiceInfo> mapLocalHost;
static bool vfLimited[NET_MAX] = {};
static CNode* pnodeLocalHost = NULL;