Lines Matching +full:0 +full:- +full:7 +full:a +full:- +full:e
14 taken in conjunction with other tracepoints to build a "Big Picture" of
15 what is going on within the system. There are a large number of methods for
27 ----------------------
32 $ find /sys/kernel/tracing/events -type d
34 will give a fair indication of the number of events available.
37 ----------------------------------------
40 are available with the perf tool. Getting a list of available events is a
55 3.1 System-Wide Event Enabling
56 ------------------------------
58 See Documentation/trace/events.rst for a proper description on how events
59 can be enabled system-wide. A short example of enabling all events related
62 $ for i in `find /sys/kernel/tracing/events -name "enable" | grep mm_`; do echo 1 > $i; done
64 3.2 System-Wide Event Enabling with SystemTap
65 ---------------------------------------------
79 printf ("%-25s %-s\n", "#Pages Allocated", "Process Name")
80 foreach (proc in page_allocs-)
81 printf("%-25d %s\n", page_allocs[proc], proc)
90 3.3 System-Wide Event Enabling with PCL
91 ---------------------------------------
93 By specifying the -a switch and analysing sleep, the system-wide events
94 for a duration of time can be examined.
97 $ perf stat -a \
98 -e kmem:mm_page_alloc -e kmem:mm_page_free \
99 -e kmem:mm_page_free_batched \
109 Similarly, one could execute a shell and exit it as desired to get a report
113 ------------------------
115 Documentation/trace/ftrace.rst describes how to enable events on a per-thread
119 -----------------------------------
121 Events can be activated and tracked for the duration of a process on a local
125 $ perf stat -e kmem:mm_page_alloc -e kmem:mm_page_free \
126 -e kmem:mm_page_free_batched ./hackbench 10
140 Documentation/trace/ftrace.rst covers in-depth how to filter events in
153 $ perf stat --repeat 5 -e kmem:mm_page_alloc -e kmem:mm_page_free
154 -e kmem:mm_page_free_batched ./hackbench 10
163 16630 kmem:mm_page_alloc ( +- 3.542% )
164 11486 kmem:mm_page_free ( +- 4.771% )
165 4730 kmem:mm_page_free_batched ( +- 2.325% )
167 0.982653002 seconds time elapsed ( +- 1.448% )
169 In the event that some higher-level event is required that depends on some
170 aggregation of discrete events, then a script would need to be developed.
172 Using --repeat, it is also possible to view how events are fluctuating over
173 time on a system-wide basis using -a and sleep.
176 $ perf stat -e kmem:mm_page_alloc -e kmem:mm_page_free \
177 -e kmem:mm_page_free_batched \
178 -a --repeat 10 \
182 1066 kmem:mm_page_alloc ( +- 26.148% )
183 182 kmem:mm_page_free ( +- 5.464% )
184 890 kmem:mm_page_free_batched ( +- 30.079% )
186 1.002251757 seconds time elapsed ( +- 0.005% )
188 6. Higher-Level Analysis with Helper Scripts
192 /sys/kernel/tracing/trace_pipe in human-readable format although binary
193 options exist as well. By post-processing the output, further information can
194 be gathered on-line as appropriate. Examples of post-processing might include
196 - Reading information from /proc for the PID that triggered the event
197 - Deriving a higher-level event from a series of lower-level events.
198 - Calculating latencies between two events
200 Documentation/trace/postprocess/trace-pagealloc-postprocess.pl is an example
201 script that can read trace_pipe from STDIN or a copy of a trace. When used
202 on-line, it can be interrupted once to generate a report without exiting
208 - Derive high-level events from many low-level events. If a number of pages
209 are freed to the main allocator from the per-CPU lists, it recognises
210 that as one per-CPU drain even though there is no specific tracepoint
212 - It can aggregate based on PID or individual process number
213 - In the event memory is getting externally fragmented, it reports
215 - When receiving an event about a PID, it can record who the parent was so
216 that if large numbers of events are coming from very short-lived
220 7. Lower-Level Analysis with PCL
223 There may also be a requirement to identify what functions within a program
228 $ perf record -c 1 \
229 -e kmem:mm_page_alloc -e kmem:mm_page_free \
230 -e kmem:mm_page_free_batched \
235 Note the use of '-c 1' to set the event period to sample. The default sample
237 very coarse as a result.
239 This record outputted a file called perf.data which can be analysed using
250 6.85% hackbench /lib/i686/cmov/libc-2.9.so
251 2.62% hackbench /lib/ld-2.9.so
255 0.02% perf /lib/i686/cmov/libc-2.9.so
257 0.01% perf /lib/ld-2.9.so
258 0.00% hackbench /lib/i686/cmov/libpthread-2.9.so
260 # (For more details, try: perf report --sort comm,dso,symbol)
265 take a slightly different example. In the course of writing this, it was
270 $ perf record -c 1 -f \
271 -e kmem:mm_page_alloc -e kmem:mm_page_free \
272 -e kmem:mm_page_free_batched \
273 -p `pidof X`
275 This was interrupted after a few seconds and
285 47.95% Xorg /opt/gfx-test/lib/libpixman-1.so.0.13.1
286 0.09% Xorg /lib/i686/cmov/libc-2.9.so
289 # (For more details, try: perf report --sort comm,dso,symbol)
292 So, almost half of the events are occurring in a library. To get an idea which
296 $ perf report --sort comm,dso,symbol
302 51.95% Xorg [vdso] [.] 0x000000ffffe424
303 47.93% Xorg /opt/gfx-test/lib/libpixman-1.so.0.13.1 [.] pixmanFillsse2
304 0.09% Xorg /lib/i686/cmov/libc-2.9.so [.] _int_malloc
305 0.01% Xorg /opt/gfx-test/lib/libpixman-1.so.0.13.1 [.] pixman_region32_copy_f
307 0.01% Xorg /opt/gfx-test/lib/libpixman-1.so.0.13.1 [.] get_fast_path
315 0.00 : 34eeb: 0f 18 08 prefetcht0 (%eax)
321 12.40 : 34eee: 66 0f 7f 80 40 ff ff movdqa %xmm0,-0xc0(%eax)
323 12.40 : 34ef6: 66 0f 7f 80 50 ff ff movdqa %xmm0,-0xb0(%eax)
325 12.39 : 34efe: 66 0f 7f 80 60 ff ff movdqa %xmm0,-0xa0(%eax)
327 12.67 : 34f06: 66 0f 7f 80 70 ff ff movdqa %xmm0,-0x90(%eax)
329 12.58 : 34f0e: 66 0f 7f 40 80 movdqa %xmm0,-0x80(%eax)
330 12.31 : 34f13: 66 0f 7f 40 90 movdqa %xmm0,-0x70(%eax)
331 12.40 : 34f18: 66 0f 7f 40 a0 movdqa %xmm0,-0x60(%eax)
332 12.31 : 34f1d: 66 0f 7f 40 b0 movdqa %xmm0,-0x50(%eax)
334 At a glance, it looks like the time is being spent copying pixmaps to
336 are being copied around so much but a starting point would be to take an