--- /dev/null
+/*
+ * Cell Broadband Engine OProfile Support
+ *
+ * (C) Copyright IBM Corporation 2006
+ *
+ * Authors: Maynard Johnson <maynardj@us.ibm.com>
+ * Carl Love <carll@us.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/hrtimer.h>
+#include <linux/smp.h>
+#include <linux/slab.h>
+#include <asm/cell-pmu.h>
+#include "pr_util.h"
+
+#define TRACE_ARRAY_SIZE 1024
+#define SCALE_SHIFT 14
+
+static u32 *samples;
+
+static int spu_prof_running;
+static unsigned int profiling_interval;
+
+#define NUM_SPU_BITS_TRBUF 16
+#define SPUS_PER_TB_ENTRY 4
+#define SPUS_PER_NODE 8
+
+#define SPU_PC_MASK 0xFFFF
+
+static DEFINE_SPINLOCK(sample_array_lock);
+unsigned long sample_array_lock_flags;
+
+void set_spu_profiling_frequency(unsigned int freq_khz, unsigned int cycles_reset)
+{
+ unsigned long ns_per_cyc;
+
+ if (!freq_khz)
+ freq_khz = ppc_proc_freq/1000;
+
+ /* To calculate a timeout in nanoseconds, the basic
+ * formula is ns = cycles_reset * (NSEC_PER_SEC / cpu frequency).
+ * To avoid floating point math, we use the scale math
+ * technique as described in linux/jiffies.h. We use
+ * a scale factor of SCALE_SHIFT, which provides 4 decimal places
+ * of precision. This is close enough for the purpose at hand.
+ *
+ * The value of the timeout should be small enough that the hw
+ * trace buffer will not get more then about 1/3 full for the
+ * maximum user specified (the LFSR value) hw sampling frequency.
+ * This is to ensure the trace buffer will never fill even if the
+ * kernel thread scheduling varies under a heavy system load.
+ */
+
+ ns_per_cyc = (USEC_PER_SEC << SCALE_SHIFT)/freq_khz;
+ profiling_interval = (ns_per_cyc * cycles_reset) >> SCALE_SHIFT;
+
+}
+
+/*
+ * Extract SPU PC from trace buffer entry
+ */
+static void spu_pc_extract(int cpu, int entry)
+{
+ /* the trace buffer is 128 bits */
+ u64 trace_buffer[2];
+ u64 spu_mask;
+ int spu;
+
+ spu_mask = SPU_PC_MASK;
+
+ /* Each SPU PC is 16 bits; hence, four spus in each of
+ * the two 64-bit buffer entries that make up the
+ * 128-bit trace_buffer entry. Process two 64-bit values
+ * simultaneously.
+ * trace[0] SPU PC contents are: 0 1 2 3
+ * trace[1] SPU PC contents are: 4 5 6 7
+ */
+
+ cbe_read_trace_buffer(cpu, trace_buffer);
+
+ for (spu = SPUS_PER_TB_ENTRY-1; spu >= 0; spu--) {
+ /* spu PC trace entry is upper 16 bits of the
+ * 18 bit SPU program counter
+ */
+ samples[spu * TRACE_ARRAY_SIZE + entry]
+ = (spu_mask & trace_buffer[0]) << 2;
+ samples[(spu + SPUS_PER_TB_ENTRY) * TRACE_ARRAY_SIZE + entry]
+ = (spu_mask & trace_buffer[1]) << 2;
+
+ trace_buffer[0] = trace_buffer[0] >> NUM_SPU_BITS_TRBUF;
+ trace_buffer[1] = trace_buffer[1] >> NUM_SPU_BITS_TRBUF;
+ }
+}
+
+static int cell_spu_pc_collection(int cpu)
+{
+ u32 trace_addr;
+ int entry;
+
+ /* process the collected SPU PC for the node */
+
+ entry = 0;
+
+ trace_addr = cbe_read_pm(cpu, trace_address);
+ while (!(trace_addr & CBE_PM_TRACE_BUF_EMPTY)) {
+ /* there is data in the trace buffer to process */
+ spu_pc_extract(cpu, entry);
+
+ entry++;
+
+ if (entry >= TRACE_ARRAY_SIZE)
+ /* spu_samples is full */
+ break;
+
+ trace_addr = cbe_read_pm(cpu, trace_address);
+ }
+
+ return entry;
+}
+
+
+static enum hrtimer_restart profile_spus(struct hrtimer *timer)
+{
+ ktime_t kt;
+ int cpu, node, k, num_samples, spu_num;
+
+ if (!spu_prof_running)
+ goto stop;
+
+ for_each_online_cpu(cpu) {
+ if (cbe_get_hw_thread_id(cpu))
+ continue;
+
+ node = cbe_cpu_to_node(cpu);
+
+ /* There should only be one kernel thread at a time processing
+ * the samples. In the very unlikely case that the processing
+ * is taking a very long time and multiple kernel threads are
+ * started to process the samples. Make sure only one kernel
+ * thread is working on the samples array at a time. The
+ * sample array must be loaded and then processed for a given
+ * cpu. The sample array is not per cpu.
+ */
+ spin_lock_irqsave(&sample_array_lock,
+ sample_array_lock_flags);
+ num_samples = cell_spu_pc_collection(cpu);
+
+ if (num_samples == 0) {
+ spin_unlock_irqrestore(&sample_array_lock,
+ sample_array_lock_flags);
+ continue;
+ }
+
+ for (k = 0; k < SPUS_PER_NODE; k++) {
+ spu_num = k + (node * SPUS_PER_NODE);
+ spu_sync_buffer(spu_num,
+ samples + (k * TRACE_ARRAY_SIZE),
+ num_samples);
+ }
+
+ spin_unlock_irqrestore(&sample_array_lock,
+ sample_array_lock_flags);
+
+ }
+ smp_wmb(); /* insure spu event buffer updates are written */
+ /* don't want events intermingled... */
+
+ kt = ktime_set(0, profiling_interval);
+ if (!spu_prof_running)
+ goto stop;
+ hrtimer_forward(timer, timer->base->get_time(), kt);
+ return HRTIMER_RESTART;
+
+ stop:
+ printk(KERN_INFO "SPU_PROF: spu-prof timer ending\n");
+ return HRTIMER_NORESTART;
+}
+
+static struct hrtimer timer;
+/*
+ * Entry point for SPU profiling.
+ * NOTE: SPU profiling is done system-wide, not per-CPU.
+ *
+ * cycles_reset is the count value specified by the user when
+ * setting up OProfile to count SPU_CYCLES.
+ */
+int start_spu_profiling(unsigned int cycles_reset)
+{
+ ktime_t kt;
+
+ pr_debug("timer resolution: %lu\n", TICK_NSEC);
+ kt = ktime_set(0, profiling_interval);
+ hrtimer_init(&timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ timer.expires = kt;
+ timer.function = profile_spus;
+
+ /* Allocate arrays for collecting SPU PC samples */
+ samples = kzalloc(SPUS_PER_NODE *
+ TRACE_ARRAY_SIZE * sizeof(u32), GFP_KERNEL);
+
+ if (!samples)
+ return -ENOMEM;
+
+ spu_prof_running = 1;
+ hrtimer_start(&timer, kt, HRTIMER_MODE_REL);
+
+ return 0;
+}
+
+void stop_spu_profiling(void)
+{
+ spu_prof_running = 0;
+ hrtimer_cancel(&timer);
+ kfree(samples);
+ pr_debug("SPU_PROF: stop_spu_profiling issued\n");
+}
projects / linux-2.6-omap-h63xx.git / blobdiff