mirror of https://gitee.com/openkylin/linux.git
19 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Jiri Olsa
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dd1d0044dd |
perf jvmti: Separate jvmti cmlr check
The Compiled Method Load Record (cmlr) is JDK specific interface to access JVM stack info. This makes the jvmti agent code not compile under another jdk, which does not support that. Separating jvmti cmlr check into special feature check, and adding HAVE_JVMTI_CMLR macro to indicate that. Mark cmlr code in jvmti/libjvmti.c with HAVE_JVMTI_CMLR, so we can compile it on system without cmlr support. This change makes the jvmti compile with java-1.8.0-ibm package. It's without the line numbers support, but the rest works. Adding NO_JVMTI_CMLR compile variable for testing. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ben Gainey <ben.gainey@arm.com> Cc: Gustavo Luiz Duarte <gduarte@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/20181121154341.21521-1-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Gustavo Romero
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6ac2226229 |
perf tools: Fix undefined symbol scnprintf in libperf-jvmti.so
Currently jvmti agent can not be used because function scnprintf is not present in the agent libperf-jvmti.so. As a result the JVM when using such agent to record JITed code profiling information will fail on looking up scnprintf: java: symbol lookup error: lib/libperf-jvmti.so: undefined symbol: scnprintf This commit fixes that by reverting to the use of snprintf, that can be looked up, instead of scnprintf, adding a proper check for the returned value in order to print a better error message when the jitdump file pathname is too long. Checking the returned value also helps to comply with some recent gcc versions, like gcc8, which will fail due to truncated writing checks related to the -Werror=format-truncation= flag. Signed-off-by: Gustavo Romero <gromero@linux.vnet.ibm.com> Acked-by: Jiri Olsa <jolsa@kernel.org> LPU-Reference: 1541117601-18937-2-git-send-email-gromero@linux.vnet.ibm.com Link: https://lkml.kernel.org/n/tip-mvpxxxy7wnzaj74cq75muw3f@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Jiri Olsa
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a09603f851 |
perf tools: Fix compilation errors on gcc8
We are getting following warnings on gcc8 that break compilation:
$ make
CC jvmti/jvmti_agent.o
jvmti/jvmti_agent.c: In function ‘jvmti_open’:
jvmti/jvmti_agent.c:252:35: error: ‘/jit-’ directive output may be truncated \
writing 5 bytes into a region of size between 1 and 4096 [-Werror=format-truncation=]
snprintf(dump_path, PATH_MAX, "%s/jit-%i.dump", jit_path, getpid());
There's no point in checking the result of snprintf call in
jvmti_open, the following open call will fail in case the
name is mangled or too long.
Using tools/lib/ function scnprintf that touches the return value from
the snprintf() calls and thus get rid of those warnings.
$ make DEBUG=1
CC arch/x86/util/perf_regs.o
arch/x86/util/perf_regs.c: In function ‘arch_sdt_arg_parse_op’:
arch/x86/util/perf_regs.c:229:4: error: ‘strncpy’ output truncated before terminating nul
copying 2 bytes from a string of the same length [-Werror=stringop-truncation]
strncpy(prefix, "+0", 2);
^~~~~~~~~~~~~~~~~~~~~~~~
Using scnprintf instead of the strncpy (which we know is safe in here)
to get rid of that warning.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180702134202.17745-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Ben Gainey
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ca58d7e64b |
perf jvmti: Generate correct debug information for inlined code
tools/perf/jvmti is broken in so far as it generates incorrect debug
information. Specifically it attributes all debug lines to the original
method being output even in the case that some code is being inlined
from elsewhere. This patch fixes the issue.
To test (from within linux/tools/perf):
export JDIR=/usr/lib/jvm/java-8-openjdk-amd64/
make
cat << __EOF > Test.java
public class Test
{
private StringBuilder b = new StringBuilder();
private void loop(int i, String... args)
{
for (String a : args)
b.append(a);
long hc = b.hashCode() * System.nanoTime();
b = new StringBuilder();
b.append(hc);
System.out.printf("Iteration %d = %d\n", i, hc);
}
public void run(String... args)
{
for (int i = 0; i < 10000; ++i)
{
loop(i, args);
}
}
public static void main(String... args)
{
Test t = new Test();
t.run(args);
}
}
__EOF
$JDIR/bin/javac Test.java
./perf record -F 10000 -g -k mono $JDIR/bin/java -agentpath:`pwd`/libperf-jvmti.so Test
./perf inject --jit -i perf.data -o perf.data.jitted
./perf annotate -i perf.data.jitted --stdio | grep Test\.java: | sort -u
Before this patch, Test.java line numbers get reported that are greater
than the number of lines in the Test.java file. They come from the
source file of the inlined function, e.g. java/lang/String.java:1085.
For further validation one can examine those lines in the JDK source
distribution and confirm that they map to inlined functions called by
Test.java.
After this patch, the filename of the inlined function is output
rather than the incorrect original source filename.
Signed-off-by: Ben Gainey <ben.gainey@arm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Stephane Eranian <eranian@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ben Gainey <ben.gainey@arm.com>
Cc: Colin King <colin.king@canonical.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes:
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Greg Kroah-Hartman
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b24413180f |
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Colin Ian King
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19f0edb980 |
perf jit: fix typo: "incalid" -> "invalid"
Trivial fix to typo in jvmti_close() warnx warning message. Signed-off-by: Colin King <colin.king@canonical.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/20170627124917.19151-1-colin.king@canonical.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Arnaldo Carvalho de Melo
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0353631aa7 |
perf tools: Use __maybe_unused consistently
Instead of defining __unused or redefining __maybe_unused. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/n/tip-4eleto5pih31jw1q4dypm9pf@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Jiri Olsa
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8c9c3d2f95 |
perf kvmti: Remove unused Makefile file
Now when jvmti compilation is plugged into Makefile.perf, there's no need for this makefile. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Stephane Eranian <eranian@google.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: William Cohen <wcohen@redhat.com> Link: http://lkml.kernel.org/r/20161112121016.GA17194@krava Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Jiri Olsa
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d4dfdf00d4 |
perf jvmti: Plug compilation into perf build
Compile jvmti agent as part of the perf build. The agent library is
called libperf-jvmti.so and is installed in default place together with
other files:
$ make libperf-jvmti.so
BUILD: Doing 'make -j4' parallel build
...
CC jvmti/libjvmti.o
CC jvmti/jvmti_agent.o
LD jvmti/jvmti-in.o
LINK libperf-jvmti.so
$ make DESTDIR=/tmp/krava/ install-bin
...
$ find /tmp/krava/ | grep libperf
/tmp/krava/lib64/libperf-jvmti.so
/tmp/krava/lib64/libperf-gtk.so
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Stephane Eranian <eranian@google.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: William Cohen <wcohen@redhat.com>
Link: http://lkml.kernel.org/r/1478093749-5602-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Stephane Eranian
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13b9012ab4 |
perf jit: Remove unecessary padding in jitdump file
This patch removes all the string padding generated in the jitdump file. They are not necessary and were adding unnecessary complexity. Modern processors can handle unaligned accesses quite well. The perf.data/ jitdump file are always post-processed, no need to add extra complexity for no real gain. Signed-off-by: Stephane Eranian <eranian@google.com> Cc: Anton Blanchard <anton@ozlabs.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1476356383-30100-4-git-send-email-eranian@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Stephane Eranian
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cdd75e3b0d |
perf jit: Improve error messages from JVMTI
This patch improves the usefulness of error messages generated by the JVMTI interfac.e This can help identify the root cause of a problem by printing the actual error code. The patch adds a new helper function called print_error(). Signed-off-by: Stephane Eranian <eranian@google.com> Cc: Anton Blanchard <anton@ozlabs.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Nilay Vaish <nilayvaish@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1476356383-30100-2-git-send-email-eranian@google.com [ Handle failure to convert numeric error to a string in print_error() ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Anton Blanchard
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53613e0054 |
perf jit: Fix build issue on Ubuntu
When building on Ubuntu 16.04, I get the following error: Makefile:49: *** the openjdk development package appears to me missing, install and try again. Stop. The problem is that update-java-alternatives has multiple spaces between fields, and cut treats each space as a new delimiter: java-1.8.0-openjdk-ppc64el 1081 /usr/lib/jvm/java-1.8.0-openjdk-ppc64el Fix this by using awk, which handles this fine. Signed-off-by: Anton Blanchard <anton@samba.org> Reviewed-by: Stephane Eranian <eranian@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1476325243-15788-1-git-send-email-anton@ozlabs.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Dan Carpenter
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9fcfcdf3c7 |
perf jit: Remove some no-op error handling
The 'info.e_machine' struct member is an uint16_t so 'm' is never less than zero. It looks like this was maybe left over code from earlier versions so I've just removed it. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: kernel-janitors@vger.kernel.org Link: http://lkml.kernel.org/r/20160715210836.GB19522@mwanda Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Dan Carpenter
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e03141db36 |
perf jit: Add missing curly braces
It doesn't change the runtime behavior, but my static checker complains that curly braces were intended. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: kernel-janitors@vger.kernel.org Link: http://lkml.kernel.org/r/20160715210712.GA19522@mwanda Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Adrian Hunter
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2a28e23049 |
perf jit: Add support for using TSC as a timestamp
Intel PT uses TSC as a timestamp, so add support for using TSC instead of the monotonic clock. Use of TSC is selected by an environment variable "JITDUMP_USE_ARCH_TIMESTAMP" and flagged in the jitdump file with flag JITDUMP_FLAGS_ARCH_TIMESTAMP. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1457426330-30226-1-git-send-email-adrian.hunter@intel.com [ Added the fixup from He Kuang to make it build on other arches, ] [ such as aarch64, to avoid inserting this bisectiong breakage upstream ] Link: http://lkml.kernel.org/r/1459482572-129494-1-git-send-email-hekuang@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Stephane Eranian
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7e9551bc72 |
perf jvmti: improve error message in Makefile
This patch improves the error message given by jvmti Makefile when the alternatives command cannot be found. It now suggests the user locates the root of their Java installation and pass it with JDIR= Signed-off-by: Stephane Eranian <eranian@google.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1456378056-18812-1-git-send-email-eranian@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Stephane Eranian
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d646ae0a73 |
perf jvmti: Add check for java alternatives cmd in Makefile
This patch modifies the jvmti makefile to check if the /usr/sbin/java-update-alternatives utility is present. If so, then use it, if not then use the altenatives command. This helps handle the difference between Ubuntu and Fedora Linux distributions. Signed-off-by: Stephane Eranian <eranian@google.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1455604661-9357-1-git-send-email-eranian@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Stephane Eranian
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598b7c6919 |
perf jit: add source line info support
This patch adds source line information support to perf for jitted code. The source line info must be emitted by the runtime, such as JVMTI. Perf injects extract the source line info from the jitdump file and adds the corresponding .debug_lines section in the ELF image generated for each jitted function. The source line enables matching any address in the profile with a source file and line number. The improvement is visible in perf annotate with the source code displayed alongside the assembly code. The dwarf code leverages the support from OProfile which is also released under GPLv2. Copyright 2007 OProfile authors. Signed-off-by: Stephane Eranian <eranian@google.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Carl Love <cel@us.ibm.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: John McCutchan <johnmccutchan@google.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Pawel Moll <pawel.moll@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sonny Rao <sonnyrao@chromium.org> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1448874143-7269-5-git-send-email-eranian@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Stephane Eranian
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209045adc2 |
perf tools: add JVMTI agent library
This is a standalone JVMTI library to help profile Java jitted code with perf
record/perf report. The library is not installed or compiled automatically by
perf Makefile. It is not used directly by perf. It is arch agnostic and has
been tested on X86 and ARM. It needs to be used with a Java runtime, such as
OpenJDK, as follows:
$ java -agentpath:libjvmti.so .......
See the "Committer Notes" below on how to build it.
When used this way, java will generate a jitdump binary file in
$HOME/.debug/java/jit/java-jit-*
This binary dump file contains information to help symbolize and
annotate jitted code.
The jitdump information must be injected into the perf.data file
using:
$ perf inject --jit -i perf.data -o perf.data.jitted
This injects the MMAP records to cover the jitted code and also generates
one ELF image for each jitted function. The ELF images are created in the
same subdir as the jitdump file. The MMAP records point there too.
Then, to visualize the function or asm profile, simply use the regular
perf commands:
$ perf report -i perf.data.jitted
or
$ perf annotate -i perf.data.jitted
JVMTI agent code adapted from the OProfile's opagent code.
This version of the JVMTI agent is using the CLOCK_MONOTONIC as the time
source to timestamp jit samples. To correlate with perf_events samples,
it needs to run on kernel 4.0.0-rc5+ or later with the following commit
from Peter Zijlstra:
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