Commit | Line | Data |
---|---|---|
1474855d BN |
1 | /* |
2 | * Cell Broadband Engine OProfile Support | |
3 | * | |
4 | * (C) Copyright IBM Corporation 2006 | |
5 | * | |
6 | * Authors: Maynard Johnson <maynardj@us.ibm.com> | |
7 | * Carl Love <carll@us.ibm.com> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU General Public License | |
11 | * as published by the Free Software Foundation; either version | |
12 | * 2 of the License, or (at your option) any later version. | |
13 | */ | |
14 | ||
15 | #include <linux/hrtimer.h> | |
16 | #include <linux/smp.h> | |
17 | #include <linux/slab.h> | |
18 | #include <asm/cell-pmu.h> | |
19 | #include "pr_util.h" | |
20 | ||
1474855d BN |
21 | #define SCALE_SHIFT 14 |
22 | ||
23 | static u32 *samples; | |
24 | ||
88382329 CL |
25 | /* spu_prof_running is a flag used to indicate if spu profiling is enabled |
26 | * or not. It is set by the routines start_spu_profiling_cycles() and | |
27 | * start_spu_profiling_events(). The flag is cleared by the routines | |
28 | * stop_spu_profiling_cycles() and stop_spu_profiling_events(). These | |
29 | * routines are called via global_start() and global_stop() which are called in | |
30 | * op_powerpc_start() and op_powerpc_stop(). These routines are called once | |
31 | * per system as a result of the user starting/stopping oprofile. Hence, only | |
32 | * one CPU per user at a time will be changing the value of spu_prof_running. | |
33 | * In general, OProfile does not protect against multiple users trying to run | |
34 | * OProfile at a time. | |
35 | */ | |
a5598ca0 | 36 | int spu_prof_running; |
1474855d BN |
37 | static unsigned int profiling_interval; |
38 | ||
39 | #define NUM_SPU_BITS_TRBUF 16 | |
40 | #define SPUS_PER_TB_ENTRY 4 | |
1474855d BN |
41 | |
42 | #define SPU_PC_MASK 0xFFFF | |
43 | ||
88382329 | 44 | DEFINE_SPINLOCK(oprof_spu_smpl_arry_lck); |
9b93418e | 45 | unsigned long oprof_spu_smpl_arry_lck_flags; |
1474855d BN |
46 | |
47 | void set_spu_profiling_frequency(unsigned int freq_khz, unsigned int cycles_reset) | |
48 | { | |
49 | unsigned long ns_per_cyc; | |
50 | ||
51 | if (!freq_khz) | |
52 | freq_khz = ppc_proc_freq/1000; | |
53 | ||
54 | /* To calculate a timeout in nanoseconds, the basic | |
55 | * formula is ns = cycles_reset * (NSEC_PER_SEC / cpu frequency). | |
56 | * To avoid floating point math, we use the scale math | |
57 | * technique as described in linux/jiffies.h. We use | |
58 | * a scale factor of SCALE_SHIFT, which provides 4 decimal places | |
59 | * of precision. This is close enough for the purpose at hand. | |
60 | * | |
61 | * The value of the timeout should be small enough that the hw | |
62 | * trace buffer will not get more then about 1/3 full for the | |
63 | * maximum user specified (the LFSR value) hw sampling frequency. | |
64 | * This is to ensure the trace buffer will never fill even if the | |
65 | * kernel thread scheduling varies under a heavy system load. | |
66 | */ | |
67 | ||
68 | ns_per_cyc = (USEC_PER_SEC << SCALE_SHIFT)/freq_khz; | |
69 | profiling_interval = (ns_per_cyc * cycles_reset) >> SCALE_SHIFT; | |
70 | ||
71 | } | |
72 | ||
73 | /* | |
74 | * Extract SPU PC from trace buffer entry | |
75 | */ | |
76 | static void spu_pc_extract(int cpu, int entry) | |
77 | { | |
78 | /* the trace buffer is 128 bits */ | |
79 | u64 trace_buffer[2]; | |
80 | u64 spu_mask; | |
81 | int spu; | |
82 | ||
83 | spu_mask = SPU_PC_MASK; | |
84 | ||
85 | /* Each SPU PC is 16 bits; hence, four spus in each of | |
86 | * the two 64-bit buffer entries that make up the | |
87 | * 128-bit trace_buffer entry. Process two 64-bit values | |
88 | * simultaneously. | |
89 | * trace[0] SPU PC contents are: 0 1 2 3 | |
90 | * trace[1] SPU PC contents are: 4 5 6 7 | |
91 | */ | |
92 | ||
93 | cbe_read_trace_buffer(cpu, trace_buffer); | |
94 | ||
95 | for (spu = SPUS_PER_TB_ENTRY-1; spu >= 0; spu--) { | |
96 | /* spu PC trace entry is upper 16 bits of the | |
97 | * 18 bit SPU program counter | |
98 | */ | |
99 | samples[spu * TRACE_ARRAY_SIZE + entry] | |
100 | = (spu_mask & trace_buffer[0]) << 2; | |
101 | samples[(spu + SPUS_PER_TB_ENTRY) * TRACE_ARRAY_SIZE + entry] | |
102 | = (spu_mask & trace_buffer[1]) << 2; | |
103 | ||
104 | trace_buffer[0] = trace_buffer[0] >> NUM_SPU_BITS_TRBUF; | |
105 | trace_buffer[1] = trace_buffer[1] >> NUM_SPU_BITS_TRBUF; | |
106 | } | |
107 | } | |
108 | ||
109 | static int cell_spu_pc_collection(int cpu) | |
110 | { | |
111 | u32 trace_addr; | |
112 | int entry; | |
113 | ||
114 | /* process the collected SPU PC for the node */ | |
115 | ||
116 | entry = 0; | |
117 | ||
118 | trace_addr = cbe_read_pm(cpu, trace_address); | |
119 | while (!(trace_addr & CBE_PM_TRACE_BUF_EMPTY)) { | |
120 | /* there is data in the trace buffer to process */ | |
121 | spu_pc_extract(cpu, entry); | |
122 | ||
123 | entry++; | |
124 | ||
125 | if (entry >= TRACE_ARRAY_SIZE) | |
126 | /* spu_samples is full */ | |
127 | break; | |
128 | ||
129 | trace_addr = cbe_read_pm(cpu, trace_address); | |
130 | } | |
131 | ||
132 | return entry; | |
133 | } | |
134 | ||
135 | ||
136 | static enum hrtimer_restart profile_spus(struct hrtimer *timer) | |
137 | { | |
138 | ktime_t kt; | |
139 | int cpu, node, k, num_samples, spu_num; | |
140 | ||
141 | if (!spu_prof_running) | |
142 | goto stop; | |
143 | ||
144 | for_each_online_cpu(cpu) { | |
145 | if (cbe_get_hw_thread_id(cpu)) | |
146 | continue; | |
147 | ||
148 | node = cbe_cpu_to_node(cpu); | |
149 | ||
150 | /* There should only be one kernel thread at a time processing | |
151 | * the samples. In the very unlikely case that the processing | |
152 | * is taking a very long time and multiple kernel threads are | |
153 | * started to process the samples. Make sure only one kernel | |
154 | * thread is working on the samples array at a time. The | |
155 | * sample array must be loaded and then processed for a given | |
156 | * cpu. The sample array is not per cpu. | |
157 | */ | |
9b93418e CL |
158 | spin_lock_irqsave(&oprof_spu_smpl_arry_lck, |
159 | oprof_spu_smpl_arry_lck_flags); | |
1474855d BN |
160 | num_samples = cell_spu_pc_collection(cpu); |
161 | ||
162 | if (num_samples == 0) { | |
9b93418e CL |
163 | spin_unlock_irqrestore(&oprof_spu_smpl_arry_lck, |
164 | oprof_spu_smpl_arry_lck_flags); | |
1474855d BN |
165 | continue; |
166 | } | |
167 | ||
168 | for (k = 0; k < SPUS_PER_NODE; k++) { | |
169 | spu_num = k + (node * SPUS_PER_NODE); | |
170 | spu_sync_buffer(spu_num, | |
171 | samples + (k * TRACE_ARRAY_SIZE), | |
172 | num_samples); | |
173 | } | |
174 | ||
9b93418e CL |
175 | spin_unlock_irqrestore(&oprof_spu_smpl_arry_lck, |
176 | oprof_spu_smpl_arry_lck_flags); | |
1474855d BN |
177 | |
178 | } | |
179 | smp_wmb(); /* insure spu event buffer updates are written */ | |
180 | /* don't want events intermingled... */ | |
181 | ||
182 | kt = ktime_set(0, profiling_interval); | |
183 | if (!spu_prof_running) | |
184 | goto stop; | |
185 | hrtimer_forward(timer, timer->base->get_time(), kt); | |
186 | return HRTIMER_RESTART; | |
187 | ||
188 | stop: | |
189 | printk(KERN_INFO "SPU_PROF: spu-prof timer ending\n"); | |
190 | return HRTIMER_NORESTART; | |
191 | } | |
192 | ||
193 | static struct hrtimer timer; | |
194 | /* | |
9b93418e | 195 | * Entry point for SPU cycle profiling. |
1474855d BN |
196 | * NOTE: SPU profiling is done system-wide, not per-CPU. |
197 | * | |
198 | * cycles_reset is the count value specified by the user when | |
199 | * setting up OProfile to count SPU_CYCLES. | |
200 | */ | |
9b93418e | 201 | int start_spu_profiling_cycles(unsigned int cycles_reset) |
1474855d BN |
202 | { |
203 | ktime_t kt; | |
204 | ||
205 | pr_debug("timer resolution: %lu\n", TICK_NSEC); | |
206 | kt = ktime_set(0, profiling_interval); | |
207 | hrtimer_init(&timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
23446d1d | 208 | hrtimer_set_expires(&timer, kt); |
1474855d BN |
209 | timer.function = profile_spus; |
210 | ||
211 | /* Allocate arrays for collecting SPU PC samples */ | |
212 | samples = kzalloc(SPUS_PER_NODE * | |
213 | TRACE_ARRAY_SIZE * sizeof(u32), GFP_KERNEL); | |
214 | ||
215 | if (!samples) | |
216 | return -ENOMEM; | |
217 | ||
218 | spu_prof_running = 1; | |
219 | hrtimer_start(&timer, kt, HRTIMER_MODE_REL); | |
a5598ca0 | 220 | schedule_delayed_work(&spu_work, DEFAULT_TIMER_EXPIRE); |
1474855d BN |
221 | |
222 | return 0; | |
223 | } | |
224 | ||
88382329 CL |
225 | /* |
226 | * Entry point for SPU event profiling. | |
227 | * NOTE: SPU profiling is done system-wide, not per-CPU. | |
228 | * | |
229 | * cycles_reset is the count value specified by the user when | |
230 | * setting up OProfile to count SPU_CYCLES. | |
231 | */ | |
232 | void start_spu_profiling_events(void) | |
233 | { | |
234 | spu_prof_running = 1; | |
235 | schedule_delayed_work(&spu_work, DEFAULT_TIMER_EXPIRE); | |
236 | ||
237 | return; | |
238 | } | |
239 | ||
9b93418e | 240 | void stop_spu_profiling_cycles(void) |
1474855d BN |
241 | { |
242 | spu_prof_running = 0; | |
243 | hrtimer_cancel(&timer); | |
244 | kfree(samples); | |
9b93418e | 245 | pr_debug("SPU_PROF: stop_spu_profiling_cycles issued\n"); |
1474855d | 246 | } |
88382329 CL |
247 | |
248 | void stop_spu_profiling_events(void) | |
249 | { | |
250 | spu_prof_running = 0; | |
251 | } |