- 14 Oct, 2008 6 commits
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Ingo Molnar authored
while it's arguably low overhead, we dont enable new features by default. Signed-off-by:Ingo Molnar <mingo@elte.hu>
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Mathieu Desnoyers authored
Porting the trace_mark() used by ftrace to tracepoints. (cleanup) Changelog : - Change error messages : marker -> tracepoint [ mingo@elte.hu: conflict resolutions ] Signed-off-by:
Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by:
'Peter Zijlstra' <peterz@infradead.org> Signed-off-by:
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Mathieu Desnoyers authored
Instrument the scheduler activity (sched_switch, migration, wakeups, wait for a task, signal delivery) and process/thread creation/destruction (fork, exit, kthread stop). Actually, kthread creation is not instrumented in this patch because it is architecture dependent. It allows to connect tracers such as ftrace which detects scheduling latencies, good/bad scheduler decisions. Tools like LTTng can export this scheduler information along with instrumentation of the rest of the kernel activity to perform post-mortem analysis on the scheduler activity. About the performance impact of tracepoints (which is comparable to markers), even without immediate values optimizations, tests done by Hideo Aoki on ia64 show no regression. His test case was using hackbench on a kernel where scheduler instrumentation (about 5 events in code scheduler code) was added. See the "Tracepoints" patch header for performance result detail. Changelog : - Change instrumentation location and parameter to match ftrace instrumentation, previously done with kernel markers. [ mingo@elte.hu: conflict resolutions ] Signed-off-by:
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Mathieu Desnoyers authored
Tracepoint example code under samples/. Signed-off-by:
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Mathieu Desnoyers authored
Documentation of tracepoint usage. Signed-off-by:
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Mathieu Desnoyers authored
Implementation of kernel tracepoints. Inspired from the Linux Kernel Markers. Allows complete typing verification by declaring both tracing statement inline functions and probe registration/unregistration static inline functions within the same macro "DEFINE_TRACE". No format string is required. See the tracepoint Documentation and Samples patches for usage examples. Taken from the documentation patch : "A tracepoint placed in code provides a hook to call a function (probe) that you can provide at runtime. A tracepoint can be "on" (a probe is connected to it) or "off" (no probe is attached). When a tracepoint is "off" it has no effect, except for adding a tiny time penalty (checking a condition for a branch) and space penalty (adding a few bytes for the function call at the end of the instrumented function and adds a data structure in a separate section). When a tracepoint is "on", the function you provide is called each time the tracepoint is executed, in the execution context of the caller. When the function provided ends its execution, it returns to the caller (continuing from the tracepoint site). You can put tracepoints at important locations in the code. They are lightweight hooks that can pass an arbitrary number of parameters, which prototypes are described in a tracepoint declaration placed in a header file." Addition and removal of tracepoints is synchronized by RCU using the scheduler (and preempt_disable) as guarantees to find a quiescent state (this is really RCU "classic"). The update side uses rcu_barrier_sched() with call_rcu_sched() and the read/execute side uses "preempt_disable()/preempt_enable()". We make sure the previous array containing probes, which has been scheduled for deletion by the rcu callback, is indeed freed before we proceed to the next update. It therefore limits the rate of modification of a single tracepoint to one update per RCU period. The objective here is to permit fast batch add/removal of probes on _different_ tracepoints. Changelog : - Use #name ":" #proto as string to identify the tracepoint in the tracepoint table. This will make sure not type mismatch happens due to connexion of a probe with the wrong type to a tracepoint declared with the same name in a different header. - Add tracepoint_entry_free_old. - Change __TO_TRACE to get rid of the 'i' iterator. Masami Hiramatsu <mhiramat@redhat.com> : Tested on x86-64. Performance impact of a tracepoint : same as markers, except that it adds about 70 bytes of instructions in an unlikely branch of each instrumented function (the for loop, the stack setup and the function call). It currently adds a memory read, a test and a conditional branch at the instrumentation site (in the hot path). Immediate values will eventually change this into a load immediate, test and branch, which removes the memory read which will make the i-cache impact smaller (changing the memory read for a load immediate removes 3-4 bytes per site on x86_32 (depending on mov prefixes), or 7-8 bytes on x86_64, it also saves the d-cache hit). About the performance impact of tracepoints (which is comparable to markers), even without immediate values optimizations, tests done by Hideo Aoki on ia64 show no regression. His test case was using hackbench on a kernel where scheduler instrumentation (about 5 events in code scheduler code) was added. Quoting Hideo Aoki about Markers : I evaluated overhead of kernel marker using linux-2.6-sched-fixes git tree, which includes several markers for LTTng, using an ia64 server. While the immediate trace mark feature isn't implemented on ia64, there is no major performance regression. So, I think that we don't have any issues to propose merging marker point patches into Linus's tree from the viewpoint of performance impact. I prepared two kernels to evaluate. The first one was compiled without CONFIG_MARKERS. The second one was enabled CONFIG_MARKERS. I downloaded the original hackbench from the following URL: http://devresources.linux-foundation.org/craiger/hackbench/src/hackbench.c I ran hackbench 5 times in each condition and calculated the average and difference between the kernels. The parameter of hackbench: every 50 from 50 to 800 The number of CPUs of the server: 2, 4, and 8 Below is the results. As you can see, major performance regression wasn't found in any case. Even if number of processes increases, differences between marker-enabled kernel and marker- disabled kernel doesn't increase. Moreover, if number of CPUs increases, the differences doesn't increase either. Curiously, marker-enabled kernel is better than marker-disabled kernel in more than half cases, although I guess it comes from the difference of memory access pattern. * 2 CPUs Number of | without | with | diff | diff | processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] | -------------------------------------------------------------- 50 | 4.811 | 4.872 | +0.061 | +1.27 | 100 | 9.854 | 10.309 | +0.454 | +4.61 | 150 | 15.602 | 15.040 | -0.562 | -3.6 | 200 | 20.489 | 20.380 | -0.109 | -0.53 | 250 | 25.798 | 25.652 | -0.146 | -0.56 | 300 | 31.260 | 30.797 | -0.463 | -1.48 | 350 | 36.121 | 35.770 | -0.351 | -0.97 | 400 | 42.288 | 42.102 | -0.186 | -0.44 | 450 | 47.778 | 47.253 | -0.526 | -1.1 | 500 | 51.953 | 52.278 | +0.325 | +0.63 | 550 | 58.401 | 57.700 | -0.701 | -1.2 | 600 | 63.334 | 63.222 | -0.112 | -0.18 | 650 | 68.816 | 68.511 | -0.306 | -0.44 | 700 | 74.667 | 74.088 | -0.579 | -0.78 | 750 | 78.612 | 79.582 | +0.970 | +1.23 | 800 | 85.431 | 85.263 | -0.168 | -0.2 | -------------------------------------------------------------- * 4 CPUs Number of | without | with | diff | diff | processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] | -------------------------------------------------------------- 50 | 2.586 | 2.584 | -0.003 | -0.1 | 100 | 5.254 | 5.283 | +0.030 | +0.56 | 150 | 8.012 | 8.074 | +0.061 | +0.76 | 200 | 11.172 | 11.000 | -0.172 | -1.54 | 250 | 13.917 | 14.036 | +0.119 | +0.86 | 300 | 16.905 | 16.543 | -0.362 | -2.14 | 350 | 19.901 | 20.036 | +0.135 | +0.68 | 400 | 22.908 | 23.094 | +0.186 | +0.81 | 450 | 26.273 | 26.101 | -0.172 | -0.66 | 500 | 29.554 | 29.092 | -0.461 | -1.56 | 550 | 32.377 | 32.274 | -0.103 | -0.32 | 600 | 35.855 | 35.322 | -0.533 | -1.49 | 650 | 39.192 | 38.388 | -0.804 | -2.05 | 700 | 41.744 | 41.719 | -0.025 | -0.06 | 750 | 45.016 | 44.496 | -0.520 | -1.16 | 800 | 48.212 | 47.603 | -0.609 | -1.26 | -------------------------------------------------------------- * 8 CPUs Number of | without | with | diff | diff | processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] | -------------------------------------------------------------- 50 | 2.094 | 2.072 | -0.022 | -1.07 | 100 | 4.162 | 4.273 | +0.111 | +2.66 | 150 | 6.485 | 6.540 | +0.055 | +0.84 | 200 | 8.556 | 8.478 | -0.078 | -0.91 | 250 | 10.458 | 10.258 | -0.200 | -1.91 | 300 | 12.425 | 12.750 | +0.325 | +2.62 | 350 | 14.807 | 14.839 | +0.032 | +0.22 | 400 | 16.801 | 16.959 | +0.158 | +0.94 | 450 | 19.478 | 19.009 | -0.470 | -2.41 | 500 | 21.296 | 21.504 | +0.208 | +0.98 | 550 | 23.842 | 23.979 | +0.137 | +0.57 | 600 | 26.309 | 26.111 | -0.198 | -0.75 | 650 | 28.705 | 28.446 | -0.259 | -0.9 | 700 | 31.233 | 31.394 | +0.161 | +0.52 | 750 | 34.064 | 33.720 | -0.344 | -1.01 | 800 | 36.320 | 36.114 | -0.206 | -0.57 | -------------------------------------------------------------- Signed-off-by:
Masami Hiramatsu <mhiramat@redhat.com> Acked-by:
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- 13 Oct, 2008 34 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tipLinus Torvalds authored
Merges oprofile, timers/hpet, x86/traps, x86/time, and x86/core misc items. * 'x86-core-v4-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (132 commits) x86: change early_ioremap to use slots instead of nesting x86: adjust dependencies for CONFIG_X86_CMOV dumpstack: x86: various small unification steps, fix x86: remove additional_cpus x86: remove additional_cpus configurability x86: improve UP kernel when CPU-hotplug and SMP is enabled dumpstack: x86: various small unification steps dumpstack: i386: make kstack= an early boot-param and add oops=panic dumpstack: x86: use log_lvl and unify trace formatting dumptrace: x86: consistently include loglevel, print stack switch dumpstack: x86: add "end" parameter to valid_stack_ptr and print_context_stack dumpstack: x86: make printk_address equal dumpstack: x86: move die_nmi to dumpstack_32.c traps: x86: finalize unification of traps.c traps: x86: make traps_32.c and traps_64.c equal traps: x86: various noop-changes preparing for unification of traps_xx.c traps: x86_64: use task_pid_nr(tsk) instead of tsk->pid in do_general_protection traps: i386: expand clear_mem_error and remove from mach_traps.h traps: x86_64: make io_check_error equal to the one on i386 traps: i386: use preempt_conditional_sti/cli in do_int3 ...
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Alan Cox authored
Original idea for this from a patch by Rodolfo Giometti which merges various bits of PPS support Signed-off-by:
Alan Cox <alan@redhat.com> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Alan Cox authored
Drop the kernel lock further and also correct cases where we set rc to an error code, and then return 0 Signed-off-by:
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Alan Cox authored
get_current_tty now does internal locking and returns a referenced object, thus our use of tty_mutex here can go away. Signed-off-by:
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Jason Wessel authored
drivers/char/tty_io.c:1413:17: warning: symbol 'buf' shadows an earlier one drivers/char/tty_io.c:1379:20: originally declared here Signed-off-by:
Jason Wessel <jason.wessel@windriver.com> Signed-off-by:
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David S. Miller authored
The multiple drivers share the minor space occupied by a particular major number, the actual index within the device name's space is indicated by the tty_driver->name_base + uart_port->line Another usable formula is (uart_driver->minor - MINOR_BASE) + port->line Use those to print the device names properly in such situations in serial_core.c and 8250.c Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
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Alan Cox authored
Closes bug #11408 by checking the card index range for command 0 Fixes the ioctl to return ENOTTY which is correct for unknown ioctls Signed-off-by:
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Alan Cox authored
Remove/fix some bogus NULL checks, comment some locking etc Signed-off-by:
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Alan Cox authored
Many tty drivers contain 'can't happen' checks against NULL pointers passed in by the tty layer. These have never been possible to occur. Even more importantly if they ever do occur we want to know as it would be a serious bug. Signed-off-by:
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Alan Cox authored
Stephen's fixes reminded me that gigaset is still rather broken so fix it up a bit Signed-off-by:
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Stephen Rothwell authored
Today's linux-next build (x86_64 allmodconfig) failed like this: /drivers/char/tty_ioctl.c: In function 'change_termios': drivers/isdn/capi/capi.c:1234: error: implicit declaration of function 'n_tty_ioctl' drivers/isdn/gigaset/ser-gigaset.c: In function 'gigaset_tty_ioctl': drivers/isdn/gigaset/ser-gigaset.c:648: error: implicit declaration of function 'n_tty_ioctl' Introduced by commit 686b5e4aea05a80e370dc931b7f4a8d03c80da54 ("tty-move-canon-specials"). I added the following patch (which may not be correct). Signed-off-by:Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by:
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Alan Cox authored
Move the set up on ldisc change into the ldisc Move the INQ/OUTQ cases into the driver not in shared ioctl code where it gives bogus answers for other ldisc values Signed-off-by:
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Alan Cox authored
Copy the simplification from the pty unix98 special case to the generic one. This allows us to kill off driver->termios_locked entirely which is nice. We have to whack bits of the cris driver as it meddles in places it shouldn't providing its own arrays that were never used anyway. Signed-off-by:
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Alan Cox authored
We need both termios and termios_locked so allocate them as one Signed-off-by:
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Alan Cox authored
The updating and moving around of the pty code added a bug where both the helper and caller free the main tty struct (the pty driver must free the o_tty pair itself however). Signed-off-by:
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Alan Cox authored
We've done the heavy lifting now its time to mop up a bit Signed-off-by:
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Sukadev Bhattiprolu authored
When creating a new pty, save the pty's inode in the tty->driver_data. Use this inode in pty_kill() to identify the devpts instance. Since we now have the inode for the pty, we can skip get_node() lookup and remove the unused get_node(). TODO: - check if the mutex_lock is needed in pty_kill(). Signed-off-by:
Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by:
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Sukadev Bhattiprolu authored
devpts_pty_new() is called when setting up a new pty and would not will not have an existing dentry or inode for the pty. So don't bother looking for an existing dentry - just create a new one. Signed-off-by:
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Sukadev Bhattiprolu authored
As pointed out by H. Peter Anvin, since the inode for the pty is known, we don't need to look it up. Signed-off-by:
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Sukadev Bhattiprolu authored
Pass-in 'inode' or 'tty' parameter to devpts interfaces. With multiple devpts instances, these parameters will be used in subsequent patches to identify the instance of devpts mounted. The parameters also help simplify devpts implementation. Changelog[v3]: - minor changes due to merge with ttydev updates - rename parameters to emphasize they are ptmx or pts inodes - pass-in tty_struct * to devpts_pty_kill() (this will help cleanup the get_node() call in a subsequent patch) Signed-off-by:
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Sukadev Bhattiprolu authored
Move tty_driver_lookup_tty() and tty_reopen() from tty_init_dev() into tty_open() (one of the two callers of tty_init_dev()). These calls are not really required in ptmx_open(), the other caller, since ptmx_open() would be setting up a new tty. Changelog[v2]: - remove the lookup and reopen calls from ptmx_open - merge with recent changes to ttydev tree Signed-off-by:
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Alan Cox authored
The majority of the remaining init_dev code is pty special cases. We refactor this code into the driver->install method. Signed-off-by:
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Alan Cox authored
Original suggestion and proposal from Sukadev Bhattiprolu. Signed-off-by:
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Alan Cox authored
We have the lookup operation abstracted which is nice for pty cleanup but we really want to abstract the add/remove entries as well so that we can pull the pty code out of the tty core and create a clear defined interface for the tty driver table. Signed-off-by:
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Alan Cox authored
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Alan Cox authored
Fix up the naming, style and extract some bits of code into the driver specific code Signed-off-by:
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Sukadev Bhattiprolu authored
Move the 'find-tty' and 'fast-track-open' parts of init_dev() to separate functions. Signed-off-by:
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Alan Cox authored
Carry on pushing code out of tty_io when it belongs to other drivers. I'm not 100% happy with some of this and it will be worth revisiting some of the exports later when the restructuring work is done. Signed-off-by:
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Alan Cox authored
Right now there are various drivers that try to use tty->count to know when they get the final close. Aristeau Rozanski showed while debugging the vt sysfs race that this isn't entirely safe. Instead of driver side tricks to work around this introduce a shutdown which is called when the tty is being destructed. This also means that the shutdown method is tied into the refcounting. Use this to rework the console close/sysfs logic. Remove lots of special case code from the tty core code. The pty code can now have a shutdown() method that replaces the special case hackery in the tree free up paths. Signed-off-by:
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Alan Cox authored
For hysterical raisins the vt layer drops and retakes locks in the write method. This is a left over from the days when user/kernel data was passed directly to the tty not pre-buffered. Signed-off-by:
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Alan Cox authored
The open path for ptmx slaves is via the ptmx device. Opening them any other way is not allowed. Vegard Nossum found that previously this was not the case and mknod foo c 128 42; cat foo would produce nasty diagnostics Signed-off-by:
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Alan Cox authored
Various people outside the tty layer still stick their noses in behind the scenes. We need to make sure they also obey the locking and referencing rules. Signed-off-by:
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Alan Cox authored
Currently it is sometimes locked by the tty mutex and sometimes by the sighand lock. The latter is in fact correct and now we can hand back referenced objects we can fix this up without problems around sleeping functions. Signed-off-by:
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Alan Cox authored
We now have the infrastructure to sort this out but rather than teaching the syscall tty lock rules we move the hard work into a tty helper Signed-off-by:
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