| Message ID | 20180803014217.30979-1-mikey@neuling.org |
|---|---|
| State | Accepted |
| Headers | show |
| Series | htm: Documentation update | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | master/apply_patch Successfully applied |
| snowpatch_ozlabs/build-multiarch | success | Test build-multiarch on branch master |
Thanks! - Alistair On Friday, 3 August 2018 11:42:17 AM AEST Michael Neuling wrote: > Signed-off-by: Michael Neuling <mikey@neuling.org> > --- > README.md | 45 +++++++++++++++++++++++++++++---------------- > 1 file changed, 29 insertions(+), 16 deletions(-) > > diff --git a/README.md b/README.md > index a698703709..878e6d3419 100644 > --- a/README.md > +++ b/README.md > @@ -329,26 +329,39 @@ $ sudo ./pdbg -p 0 getmem -ci 0x0003ffff40000000 4 |hexdump -C > 00000004 > ``` > > -### Hardware Trace Macro > +### Hardware Trace Macro (HTM) > > -Expoitation of HTM is limited to POWER9 NestHTM from the powerpc host. > -POWER8 (core and nest). > +Exploitation of HTM is limited to POWER8 Core from the powerpc host. > > -pdbg provides a `htm` command with a variety of subcommands the most > +#### Prerequisites > + > +Core HTM on POWER8 needs to run SMT1 and no power save, so you need to > +run this first: > +``` > +ppc64_cpu --smt=1 > +for i in /sys/devices/system/cpu/cpu*/cpuidle/state*/disable;do echo 1 > $i;done > +``` > +Also, using HTM requires a kernel built with both `CONFIG_PPC_MEMTRACE=y` > +(v4.14) and `CONFIG_SCOM_DEBUGFS=y`. debugfs should be mounted at > +`/sys/kernel/debug`. Ubuntu 18.04 has this by default. > + > +#### How to run HTM > + > +pdbg provides a `htm` command with a variety of sub-commands. The most > useful command is `record` which will start the trace, wait for buffer > -to fill (~1 sec), stop and then dump (~5 sec). eg. > +to fill (~1 sec), stop and then dump the trace to a file (~5 sec). eg. > +``` > +pdbg -l 0 htm core record > +``` > +pdbg -l allows users to specify CPUs using the same addressing as > +scheme as taskset -c. This can be useful for tracing workloads. eg. > ``` > -pdbg -p0 -c4 core htm record > +taskset -c 0 myworkload > +sleep 1 > +pdbg -l 0 htm core record > ``` > -There are also low level commands which can also be used: > +There are also low level htm commands which can also be used: > - `start` will configure the hardware and start tracing in wrapping mode. > - - `stop` will still stop the trace and deconfigure the hardware > - - `dump` will dump the trace to a file > + - `stop` will still stop the trace and de-configure the hardware. > + - `dump` will dump the trace to a file. > > -If you are running into a checkstop issue, `htm status` will print the > -physical address of the buffer it is tracing into and the BMC can be > -used to recover this memory after checkstop see `getmem`. > - > -Using HTM requires a kernel built with both `CONFIG_PPC_MEMTRACE=y` > -(v4.14) and `CONFIG_SCOM_DEBUGFS=y`. debugfs should be mounted at > -`/sys/kernel/debug`. Ubuntu 18.04 has this by default. >
diff --git a/README.md b/README.md index a698703709..878e6d3419 100644 --- a/README.md +++ b/README.md @@ -329,26 +329,39 @@ $ sudo ./pdbg -p 0 getmem -ci 0x0003ffff40000000 4 |hexdump -C 00000004 ``` -### Hardware Trace Macro +### Hardware Trace Macro (HTM) -Expoitation of HTM is limited to POWER9 NestHTM from the powerpc host. -POWER8 (core and nest). +Exploitation of HTM is limited to POWER8 Core from the powerpc host. -pdbg provides a `htm` command with a variety of subcommands the most +#### Prerequisites + +Core HTM on POWER8 needs to run SMT1 and no power save, so you need to +run this first: +``` +ppc64_cpu --smt=1 +for i in /sys/devices/system/cpu/cpu*/cpuidle/state*/disable;do echo 1 > $i;done +``` +Also, using HTM requires a kernel built with both `CONFIG_PPC_MEMTRACE=y` +(v4.14) and `CONFIG_SCOM_DEBUGFS=y`. debugfs should be mounted at +`/sys/kernel/debug`. Ubuntu 18.04 has this by default. + +#### How to run HTM + +pdbg provides a `htm` command with a variety of sub-commands. The most useful command is `record` which will start the trace, wait for buffer -to fill (~1 sec), stop and then dump (~5 sec). eg. +to fill (~1 sec), stop and then dump the trace to a file (~5 sec). eg. +``` +pdbg -l 0 htm core record +``` +pdbg -l allows users to specify CPUs using the same addressing as +scheme as taskset -c. This can be useful for tracing workloads. eg. ``` -pdbg -p0 -c4 core htm record +taskset -c 0 myworkload +sleep 1 +pdbg -l 0 htm core record ``` -There are also low level commands which can also be used: +There are also low level htm commands which can also be used: - `start` will configure the hardware and start tracing in wrapping mode. - - `stop` will still stop the trace and deconfigure the hardware - - `dump` will dump the trace to a file + - `stop` will still stop the trace and de-configure the hardware. + - `dump` will dump the trace to a file. -If you are running into a checkstop issue, `htm status` will print the -physical address of the buffer it is tracing into and the BMC can be -used to recover this memory after checkstop see `getmem`. - -Using HTM requires a kernel built with both `CONFIG_PPC_MEMTRACE=y` -(v4.14) and `CONFIG_SCOM_DEBUGFS=y`. debugfs should be mounted at -`/sys/kernel/debug`. Ubuntu 18.04 has this by default.
Signed-off-by: Michael Neuling <mikey@neuling.org> --- README.md | 45 +++++++++++++++++++++++++++++---------------- 1 file changed, 29 insertions(+), 16 deletions(-)