From 11845789eec5f9286b6df0e9eff408b03b4dc919 Mon Sep 17 00:00:00 2001 From: Hector Dearman Date: Thu, 8 Mar 2018 14:35:44 +0000 Subject: Atrace: Add commandline flags to enable/disable userland tracing Adds a commandline flag to Atrace for Perfetto: --only_userspace. When --only_userspace is passed atrace does everything atrace would normally do to set up/tear down tracing (set various system properties, poke services etc) but doesn't modify any ftrace settings, doesn't clear read or otherwise touch the ftrace buffer, and doesn't start or stop tracing. Perfetto allows recording and collection of ftrace kernel events (as systrace/atrace does for local devices). We currently integrate with atrace to collect non-kernel events using the async_start and async_stop command line arguments. These cause atrace to poke binder/hal services and apps then Perfetto scrapes the print ftrace events from the kernel ring buffer. There are two downsides: 1. Atrace attempts drain the ftrace buffer after Perfetto has already done so. 2. Any time Atrace starts/stops it modifies the global ftrace settings and clears the ring buffer. The second is especially unfortunate as otherwise Perfetto supports multiplexing multiple simultaneous traces. This flag would make it much easier to integrate atrace and Perfetto. To test: First enable ftrace: $ adb shell 'echo 2048 > /d/tracing/buffer_size_kb' $ adb shell 'echo > /d/tracing/trace' $ adb shell 'echo 1 > /d/tracing/tracing_on' Next turn on the input category. $ adb shell atrace --async_start --only_userspace input Touch the screen a bunch. $ adb shell cat /d/tracing/trace Now you should see many events. Next turn off the input category. $ adb shell atrace --async_stop --only_userspace Clear tracing. $ adb shell 'echo > /d/tracing/trace' Touch the screen a bunch. $ adb shell cat /d/tracing/trace You should see no events. Ftrace settings should not have been touched: $ adb shell cat /d/tracing/tracing_on Should be 1 still. $ adb shell cat /d/tracing/buffer_size_kb Should be 2048 still. Bug: 73625407 Test: see above. Change-Id: Ia43ab689c4f93280315eb984581187c1582c2b07 --- cmds/atrace/atrace.cpp | 105 ++++++++++++++++++++++++++++++++----------------- 1 file changed, 68 insertions(+), 37 deletions(-) diff --git a/cmds/atrace/atrace.cpp b/cmds/atrace/atrace.cpp index 57745ef948..3d63971516 100644 --- a/cmds/atrace/atrace.cpp +++ b/cmds/atrace/atrace.cpp @@ -774,22 +774,10 @@ static bool setCategoriesEnableFromFile(const char* categories_file) return ok; } -// Set all the kernel tracing settings to the desired state for this trace -// capture. -static bool setUpTrace() +static bool setUpUserspaceTracing() { bool ok = true; - // Set up the tracing options. - ok &= setCategoriesEnableFromFile(g_categoriesFile); - ok &= setTraceOverwriteEnable(g_traceOverwrite); - ok &= setTraceBufferSizeKB(g_traceBufferSizeKB); - // TODO: Re-enable after stabilization - //ok &= setCmdlineSize(); - ok &= setClock(); - ok &= setPrintTgidEnableIfPresent(true); - ok &= setKernelTraceFuncs(g_kernelTraceFuncs); - // Set up the tags property. uint64_t tags = 0; for (size_t i = 0; i < arraysize(k_categories); i++) { @@ -827,6 +815,37 @@ static bool setUpTrace() ok &= ServiceUtility::PokeServices(); } + return ok; +} + +static void cleanUpUserspaceTracing() +{ + setTagsProperty(0); + clearAppProperties(); + pokeBinderServices(); + + if (g_tracePdx) { + ServiceUtility::PokeServices(); + } +} + + +// Set all the kernel tracing settings to the desired state for this trace +// capture. +static bool setUpKernelTracing() +{ + bool ok = true; + + // Set up the tracing options. + ok &= setCategoriesEnableFromFile(g_categoriesFile); + ok &= setTraceOverwriteEnable(g_traceOverwrite); + ok &= setTraceBufferSizeKB(g_traceBufferSizeKB); + // TODO: Re-enable after stabilization + //ok &= setCmdlineSize(); + ok &= setClock(); + ok &= setPrintTgidEnableIfPresent(true); + ok &= setKernelTraceFuncs(g_kernelTraceFuncs); + // Disable all the sysfs enables. This is done as a separate loop from // the enables to allow the same enable to exist in multiple categories. ok &= disableKernelTraceEvents(); @@ -854,20 +873,11 @@ static bool setUpTrace() } // Reset all the kernel tracing settings to their default state. -static void cleanUpTrace() +static void cleanUpKernelTracing() { // Disable all tracing that we're able to. disableKernelTraceEvents(); - // Reset the system properties. - setTagsProperty(0); - clearAppProperties(); - pokeBinderServices(); - - if (g_tracePdx) { - ServiceUtility::PokeServices(); - } - // Set the options back to their defaults. setTraceOverwriteEnable(true); setTraceBufferSizeKB(1); @@ -875,7 +885,6 @@ static void cleanUpTrace() setKernelTraceFuncs(NULL); } - // Enable tracing in the kernel. static bool startTrace() { @@ -1107,6 +1116,7 @@ int main(int argc, char **argv) bool traceStop = true; bool traceDump = true; bool traceStream = false; + bool onlyUserspace = false; if (argc == 2 && 0 == strcmp(argv[1], "--help")) { showHelp(argv[0]); @@ -1122,12 +1132,13 @@ int main(int argc, char **argv) int ret; int option_index = 0; static struct option long_options[] = { - {"async_start", no_argument, 0, 0 }, - {"async_stop", no_argument, 0, 0 }, - {"async_dump", no_argument, 0, 0 }, - {"list_categories", no_argument, 0, 0 }, - {"stream", no_argument, 0, 0 }, - { 0, 0, 0, 0 } + {"async_start", no_argument, 0, 0 }, + {"async_stop", no_argument, 0, 0 }, + {"async_dump", no_argument, 0, 0 }, + {"only_userspace", no_argument, 0, 0 }, + {"list_categories", no_argument, 0, 0 }, + {"stream", no_argument, 0, 0 }, + { 0, 0, 0, 0 } }; ret = getopt_long(argc, argv, "a:b:cf:k:ns:t:zo:", @@ -1197,6 +1208,8 @@ int main(int argc, char **argv) async = true; traceStart = false; traceStop = false; + } else if (!strcmp(long_options[option_index].name, "only_userspace")) { + onlyUserspace = true; } else if (!strcmp(long_options[option_index].name, "stream")) { traceStream = true; traceDump = false; @@ -1214,6 +1227,14 @@ int main(int argc, char **argv) } } + if (onlyUserspace) { + if (!async || !(traceStart || traceStop)) { + fprintf(stderr, "--only_userspace can only be used with " + "--async_start or --async_stop\n"); + exit(1); + } + } + registerSigHandler(); if (g_initialSleepSecs > 0) { @@ -1221,13 +1242,19 @@ int main(int argc, char **argv) } bool ok = true; + if (traceStart) { - ok &= setUpTrace(); + ok &= setUpUserspaceTracing(); + } + + if (ok && traceStart && !onlyUserspace) { + ok &= setUpKernelTracing(); ok &= startTrace(); } if (ok && traceStart) { - if (!traceStream) { + + if (!traceStream && !onlyUserspace) { printf("capturing trace..."); fflush(stdout); } @@ -1237,7 +1264,8 @@ int main(int argc, char **argv) // contain entries from only one CPU can cause "begin" entries without a // matching "end" entry to show up if a task gets migrated from one CPU to // another. - ok = clearTrace(); + if (!onlyUserspace) + ok = clearTrace(); writeClockSyncMarker(); if (ok && !async && !traceStream) { @@ -1258,10 +1286,10 @@ int main(int argc, char **argv) } // Stop the trace and restore the default settings. - if (traceStop) + if (traceStop && !onlyUserspace) stopTrace(); - if (ok && traceDump) { + if (ok && traceDump && !onlyUserspace) { if (!g_traceAborted) { printf(" done\n"); fflush(stdout); @@ -1288,8 +1316,11 @@ int main(int argc, char **argv) } // Reset the trace buffer size to 1. - if (traceStop) - cleanUpTrace(); + if (traceStop) { + cleanUpUserspaceTracing(); + if (!onlyUserspace) + cleanUpKernelTracing(); + } return g_traceAborted ? 1 : 0; } -- cgit v1.2.3-59-g8ed1b