diff --git a/src/log.cpp b/src/log.cpp
index 9645b76..4eedeb7 100644
--- a/src/log.cpp
+++ b/src/log.cpp
@@ -48,10 +48,13 @@ namespace detail {
 static
 unsigned char abortOnCrit;
 
-const char* log_prefix(const char* name, Level lvl)
+const char* log_prep(logger& log, unsigned rawlvl)
 {
-    thread_local char prefix[64];
-    // YYYY-mm-ddTHH:MM:SS.FffFffFff
+    auto lvl = (Level)(rawlvl&0xff);
+    if(!log.test(lvl))
+        return nullptr; // don't log
+
+    thread_local char prefix[80];
 
     epicsTimeStamp now;
     size_t N;
@@ -73,25 +76,24 @@ const char* log_prefix(const char* name, Level lvl)
     default:           lname = "<\?\?\?>"; break;
     }
 
-    epicsSnprintf(prefix+N, sizeof(prefix)-N, " %s %s", lname, name);
+    int ret = epicsSnprintf(prefix+N, sizeof(prefix)-N, " %s %s", lname, log.name);
+    if(ret >=0 ) {
+        N += size_t(ret);
+        if(N>60) {
+            // prefix is too long (arbitrary), so move message content to next line
+            epicsSnprintf(prefix+N, sizeof(prefix)-N, "\n    ");
+        }
+    }
 
     return prefix;
 }
 
-void _log_printf(unsigned lvl, const char* fmt, ...)
+static
+void _log_vprintf(unsigned rawlvl, const char *fmt, va_list args)
 {
-    bool bt = lvl&0x1000;
-    auto L = Level(lvl&0xff);
-    auto abt = L==Level::Crit && abortOnCrit!=0;
+    errlogVprintf(fmt, args);
 
-    {
-        va_list args;
-        va_start(args, fmt);
-        errlogVprintf(fmt, args);
-        va_end(args);
-    }
-
-    if(abt) {
+    if(Level(rawlvl&0xff)==Level::Crit && abortOnCrit!=0) {
         errlogFlush();
         if(abortOnCrit==1) {
             // C abort, end process
@@ -103,13 +105,30 @@ void _log_printf(unsigned lvl, const char* fmt, ...)
             cantProceed("CRITICAL ERROR\n");
         }
 
-    } else if(bt) {
+    } else if(rawlvl&0x1000) {
         errlogFlush();
         epicsStackTrace();
         errlogFlush();
     }
 }
 
+void _log_printf(unsigned rawlvl, const char *fmt, ...)
+{
+    va_list args;
+    va_start(args, fmt);
+    _log_vprintf(rawlvl, fmt, args);
+    va_end(args);
+}
+
+void _log_printf_hex(unsigned rawlvl, const void *buf, size_t buflen, const char *fmt, ...)
+{
+    va_list args;
+    va_start(args, fmt);
+    xerrlogHexPrintf(buf, buflen);
+    _log_vprintf(rawlvl, fmt, args);
+    va_end(args);
+}
+
 } // namespace detail
 
 namespace {
diff --git a/src/pvxs/log.h b/src/pvxs/log.h
index fbe0473..97aaacd 100644
--- a/src/pvxs/log.h
+++ b/src/pvxs/log.h
@@ -50,10 +50,13 @@ public:
 namespace detail {
 
 PVXS_API
-const char* log_prefix(const char* name, Level lvl);
+const char *log_prep(logger& log, unsigned lvl);
 
 PVXS_API
-void _log_printf(unsigned lvl, const char* fmt, ...) EPICS_PRINTF_STYLE(2,3);
+void _log_printf(unsigned rawlvl, const char *fmt, ...) EPICS_PRINTF_STYLE(2,3);
+
+PVXS_API
+void _log_printf_hex(unsigned rawlvl, const void *buf, size_t buflen, const char *fmt, ...) EPICS_PRINTF_STYLE(4,5);
 
 } // namespace detail
 
@@ -76,8 +79,8 @@ void xerrlogHexPrintf(const void *buf, size_t buflen);
  *  @endcode
  */
 #define log_printf(LOGGER, LVL, FMT, ...) do{ \
-    if((LOGGER).test(LVL)) \
-       ::pvxs::detail:: _log_printf(unsigned(LVL), "%s " FMT, ::pvxs::detail::log_prefix((LOGGER).name, LVL), __VA_ARGS__); \
+    if(auto _log_prefix = ::pvxs::detail::log_prep(LOGGER, unsigned(LVL))) \
+        ::pvxs::detail:: _log_printf(unsigned(LVL), "%s " FMT, _log_prefix, __VA_ARGS__); \
 }while(0)
 
 /* A note about MSVC (legacy) pre-processor weirdness.
@@ -98,19 +101,16 @@ void xerrlogHexPrintf(const void *buf, size_t buflen);
  * Thus FMT is explicitly matched in the following "outer" macros.
  */
 
+#define log_exc_printf(LOGGER, FMT, ...)  log_printf(LOGGER, unsigned(::pvxs::Level::Crit)|0x1000, FMT, __VA_ARGS__)
 #define log_crit_printf(LOGGER, FMT, ...)  log_printf(LOGGER, ::pvxs::Level::Crit, FMT, __VA_ARGS__)
 #define log_err_printf(LOGGER, FMT, ...)   log_printf(LOGGER, ::pvxs::Level::Err, FMT, __VA_ARGS__)
 #define log_warn_printf(LOGGER, FMT, ...)  log_printf(LOGGER, ::pvxs::Level::Warn, FMT, __VA_ARGS__)
 #define log_info_printf(LOGGER, FMT, ...)  log_printf(LOGGER, ::pvxs::Level::Info, FMT, __VA_ARGS__)
 #define log_debug_printf(LOGGER, FMT, ...) log_printf(LOGGER, ::pvxs::Level::Debug, FMT, __VA_ARGS__)
-#define log_exc_printf(LOGGER, FMT, ...)   do{ \
-    if((LOGGER).test(::pvxs::Level::Crit)) \
-       ::pvxs::detail:: _log_printf(unsigned(::pvxs::Level::Crit)|0x1000, "%s " FMT, ::pvxs::detail::log_prefix((LOGGER).name, ::pvxs::Level::Crit), __VA_ARGS__); \
-}while(0)
 
-#define log_hex_printf(LOGGER, LVL, BUF, BUFLEN, FMT, ...) do{ if((LOGGER).test(LVL)) { \
-        xerrlogHexPrintf(BUF, BUFLEN); \
-        errlogPrintf("%s " FMT, ::pvxs::detail::log_prefix((LOGGER).name, LVL), __VA_ARGS__); } \
+#define log_hex_printf(LOGGER, LVL, BUF, BUFLEN, FMT, ...) do{ \
+    if(auto _log_prefix = ::pvxs::detail::log_prep(LOGGER, unsigned(LVL))) \
+        ::pvxs::detail:: _log_printf_hex(unsigned(LVL), BUF, BUFLEN, "%s " FMT, _log_prefix, __VA_ARGS__);\
     }while(0)
 
 //! Set level for a specific logger