diff options
Diffstat (limited to 'src/socket_base.cpp')
| -rw-r--r-- | src/socket_base.cpp | 38 |
1 files changed, 10 insertions, 28 deletions
diff --git a/src/socket_base.cpp b/src/socket_base.cpp index 682062c..8ff2a6a 100644 --- a/src/socket_base.cpp +++ b/src/socket_base.cpp @@ -40,6 +40,7 @@ #include "io_thread.hpp" #include "connect_session.hpp" #include "config.hpp" +#include "clock.hpp" #include "pipe.hpp" #include "err.hpp" #include "ctx.hpp" @@ -56,14 +57,6 @@ #include "xrep.hpp" #include "uuid.hpp" -// If the RDTSC is available we use it to prevent excessive -// polling for commands. The nice thing here is that it will work on any -// system with x86 architecture and gcc or MSVC compiler. -#if (defined __GNUC__ && (defined __i386__ || defined __x86_64__)) ||\ - (defined _MSC_VER && (defined _M_IX86 || defined _M_X64)) -#define ZMQ_DELAY_COMMANDS -#endif - zmq::socket_base_t *zmq::socket_base_t::create (int type_, class ctx_t *parent_, uint32_t slot_) { @@ -109,7 +102,7 @@ zmq::socket_base_t::socket_base_t (ctx_t *parent_, uint32_t slot_) : own_t (parent_, slot_), ctx_terminated (false), destroyed (false), - last_processing_time (0), + last_tsc (0), ticks (0), rcvmore (false) { @@ -486,7 +479,7 @@ int zmq::socket_base_t::recv (::zmq_msg_t *msg_, int flags_) // // Note that 'recv' uses different command throttling algorithm (the one // described above) from the one used by 'send'. This is because counting - // ticks is more efficient than doing rdtsc all the time. + // ticks is more efficient than doing RDTSC all the time. if (++ticks == inbound_poll_rate) { if (unlikely (process_commands (false, false) != 0)) return -1; @@ -627,35 +620,24 @@ int zmq::socket_base_t::process_commands (bool block_, bool throttle_) } else { -#if defined ZMQ_DELAY_COMMANDS + // Get the CPU's tick counter. If 0, the counter is not available. + uint64_t tsc = zmq::clock_t::rdtsc (); + // Optimised version of command processing - it doesn't have to check // for incoming commands each time. It does so only if certain time // elapsed since last command processing. Command delay varies // depending on CPU speed: It's ~1ms on 3GHz CPU, ~2ms on 1.5GHz CPU // etc. The optimisation makes sense only on platforms where getting // a timestamp is a very cheap operation (tens of nanoseconds). - if (throttle_) { - - // Get timestamp counter. -#if defined __GNUC__ - uint32_t low; - uint32_t high; - __asm__ volatile ("rdtsc" : "=a" (low), "=d" (high)); - uint64_t current_time = (uint64_t) high << 32 | low; -#elif defined _MSC_VER - uint64_t current_time = __rdtsc (); -#else -#error -#endif + if (tsc && throttle_) { + // Check whether TSC haven't jumped backwards (in case of migration // between CPU cores) and whether certain time have elapsed since // last command processing. If it didn't do nothing. - if (current_time >= last_processing_time && - current_time - last_processing_time <= max_command_delay) + if (tsc >= last_tsc && tsc - last_tsc <= max_command_delay) return 0; - last_processing_time = current_time; + last_tsc = tsc; } -#endif // Check whether there are any commands pending for this thread. rc = signaler.recv (&cmd, false); |