AlanCoopersmith Oracle Corporation Solaris Engineering X Server Version &xserver.version; 2005200620072010 Oracle and/or its affiliates. All rights reserved. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice (including the next paragraph) shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. This page provides details on a statically defined user application tracing provider for the DTrace facility in Solaris 10, MacOS X 10.5, and later releases. This provider instruments various points in the X server, to allow tracing what client applications are up to. DTrace probes may be used with SystemTap on GNU/Linux systems. The provider was integrated into the X.Org code base with Solaris 10 & OpenSolaris support for the Xserver 1.4 release, released in 2007 with X11R7.3. Support for DTrace on MacOS X was added in Xserver 1.7. These probes expose the request and reply structure of the X protocol between clients and the X server, so an understanding of that basic nature will aid in learning how to use these probes. Due to the way User-Defined DTrace probes work, arguments to these probes all bear undistinguished names of arg0, arg1, arg2, etc. These tables should help you determine what the real data is for each of the probe arguments. Probe name Description arg0 arg1 arg2 arg3 arg4 arg5 arg6 Request Probes request-start Called just before processing each client request. requestName requestCode requestLength clientId requestBuffer request-done Called just after processing each client request. requestName requestCode sequenceNumber clientId resultCode Event Probes send-event Called just before send each event to a client. clientId eventCode eventBuffer Client Connection Probes client-connect Called when a new connection is opened from a client clientId clientFD client-auth Called when client authenticates (normally just after connection opened) clientId clientAddr clientPid clientZoneId client-disconnect Called when a client connection is closed clientId Resource Allocation Probes resource-alloc Called when a new resource (pixmap, gc, colormap, etc.) is allocated resourceId resourceTypeId resourceValue resourceTypeName resource-free Called when a resource is freed resourceId resourceTypeId resourceValue resourceTypeName Input API probes input-event Called when an input event was submitted for processing deviceid eventtype button or keycode or touchid flags nvalues mask values To access data in arguments of type string, you will need to use copyinstr(). To access data buffers referenced via uintptr_t's, you will need to use copyin(). Argument name Type Description clientAddr string String representing address client connected from clientFD int X server's file descriptor for server side of each connection clientId int Unique integer identifier for each connection to the X server clientPid pid_t Process id of client, if connection is local (from getpeerucred()) clientZoneId zoneid_t Solaris: Zone id of client, if connection is local (from getpeerucred()) eventBuffer uintptr_t Pointer to buffer containing X event - decode using structures in <X11/Xproto.h> and similar headers for each extension eventCode uint8_t Event number of X event resourceId uint32_t X resource id (XID) resourceTypeId uint32_t Resource type id resourceTypeName string String representing X resource type ("PIXMAP", etc.) resourceValue uintptr_t Pointer to data for X resource resultCode int Integer code representing result status of request requestBuffer uintptr_t Pointer to buffer containing X request - decode using structures in <X11/Xproto.h> and similar headers for each extension requestCode uint8_t Request number of X request or Extension requestName string Name of X request or Extension requestLength uint16_t Length of X request sequenceNumber uint32_t Number of X request in in this connection deviceid int The device's numerical ID eventtype int Protocol event type button, keycode, touchid uint32_t The button number, keycode or touch ID flags uint32_t Miscellaneous event-specific server flags nvalues int8_t Number of bits in mask and number of elements in values mask uint8_t* Binary mask indicating which indices in values contain valid data values double* Valuator values. Values for indices for which the mask is not set are undefined This script simply increments a counter for each different request made, and when you exit the script (such as by hitting ControlC ) prints the counts. #!/usr/sbin/dtrace -s Xserver*:::request-start { @counts[copyinstr(arg0)] = count(); } The output from a short run may appear as: QueryPointer 1 CreatePixmap 2 FreePixmap 2 PutImage 2 ChangeGC 10 CopyArea 10 CreateGC 14 FreeGC 14 RENDER 28 SetClipRectangles 40 This can be rewritten slightly to cache the string containing the name of the request since it will be reused many times, instead of copying it over and over from the kernel: #!/usr/sbin/dtrace -s string Xrequest[uintptr_t]; Xserver*:::request-start /Xrequest[arg0] == ""/ { Xrequest[arg0] = copyinstr(arg0); } Xserver*:::request-start { @counts[Xrequest[arg0]] = count(); } This script records the CPU time used between the probes at the start and end of each request and aggregates it per request type. #!/usr/sbin/dtrace -s Xserver*:::request-start { reqstart = vtimestamp; } Xserver*:::request-done { @times[copyinstr(arg0)] = avg(vtimestamp - reqstart); } The output from a sample run might look like: ChangeGC 889 MapWindow 907 SetClipRectangles 1319 PolyPoint 1413 PolySegment 1434 PolyRectangle 1828 FreeCursor 1895 FreeGC 1950 CreateGC 2244 FreePixmap 2246 GetInputFocus 2249 TranslateCoords 8508 QueryTree 8846 GetGeometry 9948 CreatePixmap 12111 AllowEvents 14090 GrabServer 14791 MIT-SCREEN-SAVER 16747 ConfigureWindow 22917 SetInputFocus 28521 PutImage 240841 This script simply prints information about each client that connects or disconnects from the server while it is running. Since the provider is specified as Xserver$1 instead of Xserver* like previous examples, it won't monitor all Xserver processes running on the machine, but instead expects the process id of the X server to monitor to be specified as the argument to the script. #!/usr/sbin/dtrace -s Xserver$1:::client-connect { printf("** Client Connect: id %d\n", arg0); } Xserver$1:::client-auth { printf("** Client auth'ed: id %d => %s pid %d\n", arg0, copyinstr(arg1), arg2); } Xserver$1:::client-disconnect { printf("** Client Disconnect: id %d\n", arg0); } A sample run: # ./foo.d 5790 dtrace: script './foo.d' matched 4 probes CPU ID FUNCTION:NAME 0 15774 CloseDownClient:client-disconnect ** Client Disconnect: id 65 2 15774 CloseDownClient:client-disconnect ** Client Disconnect: id 64 0 15773 EstablishNewConnections:client-connect ** Client Connect: id 64 0 15772 AuthAudit:client-auth ** Client auth'ed: id 64 => local host pid 2034 0 15773 EstablishNewConnections:client-connect ** Client Connect: id 65 0 15772 AuthAudit:client-auth ** Client auth'ed: id 65 => local host pid 2034 0 15774 CloseDownClient:client-disconnect ** Client Disconnect: id 64 This script can be used to determine which clients are creating pixmaps in the X server, printing information about each client as it connects to help trace it back to the program on the other end of the X connection. #!/usr/sbin/dtrace -qs string Xrequest[uintptr_t]; string Xrestype[uintptr_t]; Xserver$1:::request-start /Xrequest[arg0] == ""/ { Xrequest[arg0] = copyinstr(arg0); } Xserver$1:::resource-alloc /arg3 != 0 && Xrestype[arg3] == ""/ { Xrestype[arg3] = copyinstr(arg3); } Xserver$1:::request-start /Xrequest[arg0] == "X_CreatePixmap"/ { printf("-> %s: client %d\n", Xrequest[arg0], arg3); } Xserver$1:::request-done /Xrequest[arg0] == "X_CreatePixmap"/ { printf("<- %s: client %d\n", Xrequest[arg0], arg3); } Xserver$1:::resource-alloc /Xrestype[arg3] == "PIXMAP"/ { printf("** Pixmap alloc: %08x\n", arg0); } Xserver$1:::resource-free /Xrestype[arg3] == "PIXMAP"/ { printf("** Pixmap free: %08x\n", arg0); } Xserver$1:::client-connect { printf("** Client Connect: id %d\n", arg0); } Xserver$1:::client-auth { printf("** Client auth'ed: id %d => %s pid %d\n", arg0, copyinstr(arg1), arg2); } Xserver$1:::client-disconnect { printf("** Client Disconnect: id %d\n", arg0); } Sample output from a run of this script: ** Client Connect: id 17 ** Client auth'ed: id 17 => local host pid 20273 -> X_CreatePixmap: client 17 ** Pixmap alloc: 02200009 <- X_CreatePixmap: client 17 -> X_CreatePixmap: client 15 ** Pixmap alloc: 01e00180 <- X_CreatePixmap: client 15 -> X_CreatePixmap: client 15 ** Pixmap alloc: 01e00181 <- X_CreatePixmap: client 15 -> X_CreatePixmap: client 14 ** Pixmap alloc: 01c004c8 <- X_CreatePixmap: client 14 ** Pixmap free: 02200009 ** Client Disconnect: id 17 ** Pixmap free: 01e00180 ** Pixmap free: 01e00181 This script can be used to monitor events submitted by drivers to the server for enqueuing. Due to the integration of the input API probes, some server-enqueued events will show up too. # Compile+run with # stap -g xorg.stp /usr/bin/Xorg # function print_valuators:string(nvaluators:long, mask_in:long, valuators_in:long) %{ int i; unsigned char *mask = (unsigned char*)THIS->mask_in; double *valuators = (double*)THIS->valuators_in; char str[128] = {0}; char *s = str; #define BitIsSet(ptr, bit) (((unsigned char*)(ptr))[(bit)>>3] & (1 << ((bit) & 7))) s += sprintf(s, "nval: %d ::", (int)THIS->nvaluators); for (i = 0; i < THIS->nvaluators; i++) { s += sprintf(s, " %d: ", i); if (BitIsSet(mask, i)) s += sprintf(s, "%d", (int)valuators[i]); } sprintf(THIS->__retvalue, "%s", str); %} probe process(@1).mark("input__event") { deviceid = $arg1 type = $arg2 detail = $arg3 flags = $arg4 nvaluators = $arg5 str = print_valuators(nvaluators, $arg6, $arg7) printf("Event: device %d type %d detail %d flags %#x %s\n", deviceid, type, detail, flags, str); } Sample output from a run of this script: Event: device 13 type 4 detail 1 flags 0x0 nval: 0 :: Event: device 13 type 6 detail 0 flags 0xa nval: 1 :: 0: 1 Event: device 13 type 6 detail 0 flags 0xa nval: 2 :: 0: 2 1: -1 Event: device 13 type 6 detail 0 flags 0xa nval: 2 :: 0: 2 1: -1 Event: device 13 type 6 detail 0 flags 0xa nval: 2 :: 0: 4 1: -3 Event: device 13 type 6 detail 0 flags 0xa nval: 2 :: 0: 3 1: -3 Event: device 13 type 6 detail 0 flags 0xa nval: 2 :: 0: 3 1: -2 Event: device 13 type 6 detail 0 flags 0xa nval: 2 :: 0: 2 1: -2 Event: device 13 type 6 detail 0 flags 0xa nval: 2 :: 0: 2 1: -2 Event: device 13 type 6 detail 0 flags 0xa nval: 2 :: 0: 2 1: -2 Event: device 13 type 6 detail 0 flags 0xa nval: 2 :: 0: 1: -1 Event: device 13 type 6 detail 0 flags 0xa nval: 2 :: 0: 1: -1 Event: device 13 type 5 detail 1 flags 0x0 nval: 0 ::