kernel.git/arch/sparc/kernel/perf_event.c, branch linux-3.19.y

sparc: perf: Make counting mode actually work

2015-03-26T12:59:32Z

[ Upstream commit d51291cb8f32bfae6b331e1838651f3ddefa73a5 ] Currently perf-stat (aka, counting mode) does not work: $ perf stat ls ... Performance counter stats for 'ls': 1.585665 task-clock (msec) # 0.580 CPUs utilized 24 context-switches # 0.015 M/sec 0 cpu-migrations # 0.000 K/sec 86 page-faults # 0.054 M/sec cycles stalled-cycles-frontend stalled-cycles-backend instructions branches branch-misses 0.002735100 seconds time elapsed The reason is that state is never reset (stays with PERF_HES_UPTODATE set). Add a call to sparc_pmu_enable_event during the added_event handling. Clean up the encoding since pmu_start calls sparc_pmu_enable_event which does the same. Passing PERF_EF_RELOAD to sparc_pmu_start means the call to sparc_perf_event_set_period can be removed as well. With this patch: $ perf stat ls ... Performance counter stats for 'ls': 1.552890 task-clock (msec) # 0.552 CPUs utilized 24 context-switches # 0.015 M/sec 0 cpu-migrations # 0.000 K/sec 86 page-faults # 0.055 M/sec 5,748,997 cycles # 3.702 GHz stalled-cycles-frontend:HG stalled-cycles-backend:HG 1,684,362 instructions:HG # 0.29 insns per cycle 295,133 branches:HG # 190.054 M/sec 28,007 branch-misses:HG # 9.49% of all branches 0.002815665 seconds time elapsed Signed-off-by: David Ahern Acked-by: Bob Picco Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

sparc: perf: Remove redundant perf_pmu_{en|dis}able calls

2015-03-26T12:59:32Z

[ Upstream commit 5b0d4b5514bbcce69b516d0742f2cfc84ebd6db3 ] perf_pmu_disable is called by core perf code before pmu->del and the enable function is called by core perf code afterwards. No need to call again within sparc_pmu_del. Ditto for pmu->add and sparc_pmu_add. Signed-off-by: David Ahern Acked-by: Bob Picco Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

2014-10-15T05:48:18Z

Pull percpu consistent-ops changes from Tejun Heo: "Way back, before the current percpu allocator was implemented, static and dynamic percpu memory areas were allocated and handled separately and had their own accessors. The distinction has been gone for many years now; however, the now duplicate two sets of accessors remained with the pointer based ones - this_cpu_*() - evolving various other operations over time. During the process, we also accumulated other inconsistent operations. This pull request contains Christoph's patches to clean up the duplicate accessor situation. __get_cpu_var() uses are replaced with with this_cpu_ptr() and __this_cpu_ptr() with raw_cpu_ptr(). Unfortunately, the former sometimes is tricky thanks to C being a bit messy with the distinction between lvalues and pointers, which led to a rather ugly solution for cpumask_var_t involving the introduction of this_cpu_cpumask_var_ptr(). This converts most of the uses but not all. Christoph will follow up with the remaining conversions in this merge window and hopefully remove the obsolete accessors" * 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (38 commits) irqchip: Properly fetch the per cpu offset percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t -fix ia64: sn_nodepda cannot be assigned to after this_cpu conversion. Use __this_cpu_write. percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t Revert "powerpc: Replace __get_cpu_var uses" percpu: Remove __this_cpu_ptr clocksource: Replace __this_cpu_ptr with raw_cpu_ptr sparc: Replace __get_cpu_var uses avr32: Replace __get_cpu_var with __this_cpu_write blackfin: Replace __get_cpu_var uses tile: Use this_cpu_ptr() for hardware counters tile: Replace __get_cpu_var uses powerpc: Replace __get_cpu_var uses alpha: Replace __get_cpu_var ia64: Replace __get_cpu_var uses s390: cio driver &__get_cpu_var replacements s390: Replace __get_cpu_var uses mips: Replace __get_cpu_var uses MIPS: Replace __get_cpu_var uses in FPU emulator. arm: Replace __this_cpu_ptr with raw_cpu_ptr ...

sparc64: T5 PMU

2014-09-17T01:26:40Z

The T5 (niagara5) has different PCR related HV fast trap values and a new HV API Group. This patch utilizes these and shares when possible with niagara4. We use the same sparc_pmu niagara4_pmu. Should there be new effort to obtain the MCU perf statistics then this would have to be changed. Cc: sparclinux@vger.kernel.org Signed-off-by: Bob Picco Signed-off-by: David S. Miller

sparc: Replace __get_cpu_var uses

2014-08-26T17:45:55Z

__get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. At the end of the patch set all uses of __get_cpu_var have been removed so the macro is removed too. The patch set includes passes over all arches as well. Once these operations are used throughout then specialized macros can be defined in non -x86 arches as well in order to optimize per cpu access by f.e. using a global register that may be set to the per cpu base. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Cc: sparclinux@vger.kernel.org Acked-by: David S. Miller Signed-off-by: Christoph Lameter Signed-off-by: Tejun Heo

sparc64: Fix pcr_ops initialization and usage bugs.

2014-08-12T03:45:12Z

Christopher reports that perf_event_print_debug() can crash in uniprocessor builds. The crash is due to pcr_ops being NULL. This happens because pcr_arch_init() is only invoked by smp_cpus_done() which only executes in SMP builds. init_hw_perf_events() is closely intertwined with pcr_ops being setup properly, therefore: 1) Call pcr_arch_init() early on from init_hw_perf_events(), instead of from smp_cpus_done(). 2) Do not hook up a PMU type if pcr_ops is NULL after pcr_arch_init(). 3) Move init_hw_perf_events to a later initcall so that it we will be sure to invoke pcr_arch_init() after all cpus are brought up. Finally, guard the one naked sequence of pcr_ops dereferences in __global_pmu_self() with an appropriate NULL check. Reported-by: Christopher Alexander Tobias Schulze Signed-off-by: David S. Miller

sparc64: fix sparse warnings in perf_event.c

2014-05-19T02:01:33Z

Fix following sparse warnings: kernel/perf_event.c:113:1: warning: symbol 'cpu_hw_events' was not declared. Should it be static? kernel/perf_event.c:1156:6: warning: symbol 'perf_event_grab_pmc' was not declared. Should it be static? kernel/perf_event.c:1172:6: warning: symbol 'perf_event_release_pmc' was not declared. Should it be static? kernel/perf_event.c:1672:12: warning: symbol 'init_hw_perf_events' was not declared. Should it be static? kernel/perf_event.c:1749:52: warning: incorrect type in argument 2 (different address spaces) kernel/perf_event.c:1772:60: warning: incorrect type in argument 2 (different address spaces) kernel/perf_event.c:1779:60: warning: incorrect type in argument 2 (different address spaces) Define the functions static as they are not used outside this file. Fix it so copy_from_user are supplied with pointers annotated _user Signed-off-by: Sam Ravnborg Signed-off-by: David S. Miller

sparc64: Make montmul/montsqr/mpmul usable in 32-bit threads.

2012-10-26T22:18:37Z

The Montgomery Multiply, Montgomery Square, and Multiple-Precision Multiply instructions work by loading a combination of the floating point and multiple register windows worth of integer registers with the inputs. These values are 64-bit. But for 32-bit userland processes we only save the low 32-bits of each integer register during a register spill. This is because the register window save area is in the user stack and has a fixed layout. Therefore, the only way to use these instruction in 32-bit mode is to perform the following sequence: 1) Load the top-32bits of a choosen integer register with a sentinel, say "-1". This will be in the outer-most register window. The idea is that we're trying to see if the outer-most register window gets spilled, and thus the 64-bit values were truncated. 2) Load all the inputs for the montmul/montsqr/mpmul instruction, down to the inner-most register window. 3) Execute the opcode. 4) Traverse back up to the outer-most register window. 5) Check the sentinel, if it's still "-1" store the results. Otherwise retry the entire sequence. This retry is extremely troublesome. If you're just unlucky and an interrupt or other trap happens, it'll push that outer-most window to the stack and clear the sentinel when we restore it. We could retry forever and never make forward progress if interrupts arrive at a fast enough rate (consider perf events as one example). So we have do limited retries and fallback to software which is extremely non-deterministic. Luckily it's very straightforward to provide a mechanism to let 32-bit applications use a 64-bit stack. Stacks in 64-bit mode are biased by 2047 bytes, which means that the lowest bit is set in the actual %sp register value. So if we see bit zero set in a 32-bit application's stack we treat it like a 64-bit stack. Runtime detection of such a facility is tricky, and cumbersome at best. For example, just trying to use a biased stack and seeing if it works is hard to recover from (the signal handler will need to use an alt stack, plus something along the lines of longjmp). Therefore, we add a system call to report a bitmask of arch specific features like this in a cheap and less hairy way. With help from Andy Polyakov. Signed-off-by: David S. Miller

sparc64: Fix bit twiddling in sparc_pmu_enable_event().

2012-10-16T20:05:25Z

There was a serious disconnect in the logic happening in sparc_pmu_disable_event() vs. sparc_pmu_enable_event(). Event disable is implemented by programming a NOP event into the PCR. However, event enable was not reversing this operation. Instead, it was setting the User/Priv/Hypervisor trace enable bits. That's not sparc_pmu_enable_event()'s job, that's what sparc_pmu_enable() and sparc_pmu_disable() do . The intent of sparc_pmu_enable_event() is clear, since it first clear out the event type encoding field. So fix this by OR'ing in the event encoding rather than the trace enable bits. Signed-off-by: David S. Miller

sparc64: Like x86 we should check current->mm during perf backtrace generation.

2012-10-15T00:59:40Z

If the MM is not active, only report the top-level PC. Do not try to access the address space. Signed-off-by: David S. Miller