[PATCH xserver 04/24] Remove non-smart scheduler. Don't require setitimer.

Keith Packard keithp at keithp.com
Sun Sep 20 23:16:15 PDT 2015


This allows the server to call GetTimeInMillis() after each request is
processed to avoid needing setitimer. -dumbSched now turns off the
setitimer.

Signed-off-by: Keith Packard <keithp at keithp.com>
---
 configure.ac            |  2 +-
 dix/dispatch.c          | 17 +++++++++++------
 include/dix-config.h.in |  3 +++
 include/dixstruct.h     |  4 +++-
 os/WaitFor.c            | 14 ++++----------
 os/io.c                 | 13 ++-----------
 os/utils.c              | 23 ++++++++++++-----------
 7 files changed, 36 insertions(+), 40 deletions(-)

diff --git a/configure.ac b/configure.ac
index 8d6a950..ec6b1a7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -218,7 +218,7 @@ AC_SUBST(DLOPEN_LIBS)
 dnl Checks for library functions.
 AC_CHECK_FUNCS([backtrace ffs geteuid getuid issetugid getresuid \
 	getdtablesize getifaddrs getpeereid getpeerucred getprogname getzoneid \
-	mmap seteuid shmctl64 strncasecmp vasprintf vsnprintf walkcontext])
+	mmap seteuid shmctl64 strncasecmp vasprintf vsnprintf walkcontext setitimer])
 AC_REPLACE_FUNCS([reallocarray strcasecmp strcasestr strlcat strlcpy strndup])
 
 AC_CHECK_DECLS([program_invocation_short_name], [], [], [[#include <errno.h>]])
diff --git a/dix/dispatch.c b/dix/dispatch.c
index 2c20124..aa4ec7c 100644
--- a/dix/dispatch.c
+++ b/dix/dispatch.c
@@ -222,11 +222,13 @@ UpdateCurrentTimeIf(void)
 #define SMART_SCHEDULE_DEFAULT_INTERVAL	5
 #define SMART_SCHEDULE_MAX_SLICE	15
 
-#if defined(WIN32) && !defined(__CYGWIN__)
-Bool SmartScheduleDisable = TRUE;
+#ifdef HAVE_SETITIMER
+#define SMART_SCHEDULE_DEFAULT_SIGNAL_ENABLE HAVE_SETITIMER
 #else
-Bool SmartScheduleDisable = FALSE;
+#define SMART_SCHEDULE_DEFAULT_SIGNAL_ENABLE FALSE
 #endif
+
+Bool SmartScheduleSignalEnable = SMART_SCHEDULE_DEFAULT_SIGNAL_ENABLE;
 long SmartScheduleSlice = SMART_SCHEDULE_DEFAULT_INTERVAL;
 long SmartScheduleInterval = SMART_SCHEDULE_DEFAULT_INTERVAL;
 long SmartScheduleMaxSlice = SMART_SCHEDULE_MAX_SLICE;
@@ -358,7 +360,7 @@ Dispatch(void)
 
         nready = WaitForSomething(clientReady);
 
-        if (nready && !SmartScheduleDisable) {
+        if (nready) {
             clientReady[0] = SmartScheduleClient(clientReady, nready);
             nready = 1;
         }
@@ -386,8 +388,8 @@ Dispatch(void)
                     ProcessInputEvents();
 
                 FlushIfCriticalOutputPending();
-                if (!SmartScheduleDisable &&
-                    (SmartScheduleTime - start_tick) >= SmartScheduleSlice) {
+                if ((SmartScheduleTime - start_tick) >= SmartScheduleSlice)
+                {
                     /* Penalize clients which consume ticks */
                     if (client->smart_priority > SMART_MIN_PRIORITY)
                         client->smart_priority--;
@@ -431,6 +433,9 @@ Dispatch(void)
                             (*client->requestVector[client->majorOp]) (client);
                     XaceHookAuditEnd(client, result);
                 }
+                if (!SmartScheduleSignalEnable)
+                    SmartScheduleTime = GetTimeInMillis();
+
 #ifdef XSERVER_DTRACE
                 if (XSERVER_REQUEST_DONE_ENABLED())
                     XSERVER_REQUEST_DONE(LookupMajorName(client->majorOp),
diff --git a/include/dix-config.h.in b/include/dix-config.h.in
index c2ba434..c0cb25a 100644
--- a/include/dix-config.h.in
+++ b/include/dix-config.h.in
@@ -518,4 +518,7 @@
 /* Listen on local socket */
 #undef LISTEN_LOCAL
 
+/* Have setitimer support */
+#undef HAVE_SETITIMER
+
 #endif /* _DIX_CONFIG_H_ */
diff --git a/include/dixstruct.h b/include/dixstruct.h
index 7575066..1bf1949 100644
--- a/include/dixstruct.h
+++ b/include/dixstruct.h
@@ -130,9 +130,11 @@ extern long SmartScheduleTime;
 extern long SmartScheduleInterval;
 extern long SmartScheduleSlice;
 extern long SmartScheduleMaxSlice;
-extern Bool SmartScheduleDisable;
+extern Bool SmartScheduleSignalEnable;
+#if HAVE_SETITIMER
 extern void SmartScheduleStartTimer(void);
 extern void SmartScheduleStopTimer(void);
+#endif
 
 #define SMART_MAX_PRIORITY  (20)
 #define SMART_MIN_PRIORITY  (-20)
diff --git a/os/WaitFor.c b/os/WaitFor.c
index 431f1a6..424cdfc 100644
--- a/os/WaitFor.c
+++ b/os/WaitFor.c
@@ -174,16 +174,10 @@ WaitForSomething(int *pClientsReady)
         if (workQueue)
             ProcessWorkQueue();
         if (XFD_ANYSET(&ClientsWithInput)) {
-            if (!SmartScheduleDisable) {
-                someReady = TRUE;
-                waittime.tv_sec = 0;
-                waittime.tv_usec = 0;
-                wt = &waittime;
-            }
-            else {
-                XFD_COPYSET(&ClientsWithInput, &clientsReadable);
-                break;
-            }
+            someReady = TRUE;
+            waittime.tv_sec = 0;
+            waittime.tv_usec = 0;
+            wt = &waittime;
         }
         if (someReady) {
             XFD_COPYSET(&AllSockets, &LastSelectMask);
diff --git a/os/io.c b/os/io.c
index 96a243d..864f44a 100644
--- a/os/io.c
+++ b/os/io.c
@@ -462,23 +462,14 @@ ReadRequestFromClient(ClientPtr client)
             )
             FD_SET(fd, &ClientsWithInput);
         else {
-            if (!SmartScheduleDisable)
-                FD_CLR(fd, &ClientsWithInput);
-            else
-                YieldControlNoInput(fd);
+            FD_CLR(fd, &ClientsWithInput);
         }
     }
     else {
         if (!gotnow)
             AvailableInput = oc;
-        if (!SmartScheduleDisable)
-            FD_CLR(fd, &ClientsWithInput);
-        else
-            YieldControlNoInput(fd);
+        FD_CLR(fd, &ClientsWithInput);
     }
-    if (SmartScheduleDisable)
-        if (++timesThisConnection >= MAX_TIMES_PER)
-            YieldControl();
     if (move_header) {
         request = (xReq *) oci->bufptr;
         oci->bufptr += (sizeof(xBigReq) - sizeof(xReq));
diff --git a/os/utils.c b/os/utils.c
index 868eb04..c23c0d1 100644
--- a/os/utils.c
+++ b/os/utils.c
@@ -71,7 +71,6 @@ __stdcall unsigned long GetTickCount(void);
 #if !defined(WIN32) || !defined(__MINGW32__)
 #include <sys/time.h>
 #include <sys/resource.h>
-# define SMART_SCHEDULE_POSSIBLE
 #endif
 #include "misc.h"
 #include <X11/X.h>
@@ -1005,10 +1004,11 @@ ProcessCommandLine(int argc, char *argv[])
             i = skip - 1;
         }
 #endif
-#ifdef SMART_SCHEDULE_POSSIBLE
+#if HAVE_SETITIMER
         else if (strcmp(argv[i], "-dumbSched") == 0) {
-            SmartScheduleDisable = TRUE;
+            SmartScheduleSignalEnable = FALSE;
         }
+#endif
         else if (strcmp(argv[i], "-schedInterval") == 0) {
             if (++i < argc) {
                 SmartScheduleInterval = atoi(argv[i]);
@@ -1024,7 +1024,6 @@ ProcessCommandLine(int argc, char *argv[])
             else
                 UseMsg();
         }
-#endif
         else if (strcmp(argv[i], "-render") == 0) {
             if (++i < argc) {
                 int policy = PictureParseCmapPolicy(argv[i]);
@@ -1208,10 +1207,10 @@ XNFstrdup(const char *s)
 void
 SmartScheduleStopTimer(void)
 {
-#ifdef SMART_SCHEDULE_POSSIBLE
+#if HAVE_SETITIMER
     struct itimerval timer;
 
-    if (SmartScheduleDisable)
+    if (!SmartScheduleSignalEnable)
         return;
     timer.it_interval.tv_sec = 0;
     timer.it_interval.tv_usec = 0;
@@ -1224,10 +1223,10 @@ SmartScheduleStopTimer(void)
 void
 SmartScheduleStartTimer(void)
 {
-#ifdef SMART_SCHEDULE_POSSIBLE
+#if HAVE_SETITIMER
     struct itimerval timer;
 
-    if (SmartScheduleDisable)
+    if (!SmartScheduleSignalEnable)
         return;
     timer.it_interval.tv_sec = 0;
     timer.it_interval.tv_usec = SmartScheduleInterval * 1000;
@@ -1237,19 +1236,21 @@ SmartScheduleStartTimer(void)
 #endif
 }
 
+#if HAVE_SETITIMER
 static void
 SmartScheduleTimer(int sig)
 {
     SmartScheduleTime += SmartScheduleInterval;
 }
+#endif
 
 void
 SmartScheduleInit(void)
 {
-#ifdef SMART_SCHEDULE_POSSIBLE
+#if HAVE_SETITIMER
     struct sigaction act;
 
-    if (SmartScheduleDisable)
+    if (!SmartScheduleSignalEnable)
         return;
 
     memset((char *) &act, 0, sizeof(struct sigaction));
@@ -1260,7 +1261,7 @@ SmartScheduleInit(void)
     sigaddset(&act.sa_mask, SIGALRM);
     if (sigaction(SIGALRM, &act, 0) < 0) {
         perror("sigaction for smart scheduler");
-        SmartScheduleDisable = TRUE;
+        SmartScheduleSignalEnable = FALSE;
     }
 #endif
 }
-- 
2.5.0



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