Name: SASSI
Owner: NVIDIA Research Projects
Description: Flexible GPGPU instrumentation
Created: 2015-06-11 20:35:18.0
Updated: 2017-12-21 06:47:42.0
Pushed: 2016-06-21 16:51:00.0
Size: 21244
Language: C++
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Releasing a new version of the SASSI binary today (4/14/2015) that includes some bug fixes and additional features.
Including a new header-file library that allows users to correlate SASS locations with the corresponding CUDA source line.
We conducted a tutorial at MICRO-48. You can check out the slide deck that we covered.
This project contains the SASSI instrumentation tool. SASSI is not part of the official CUDA toolkit, but instead is a research prototype from the Architecture Research Group at NVIDIA.
SASSI is a selective instrumentation framework for NVIDIA GPUs. SASSI stands for SASS Instrumenter, where SASS is NVIDIA's name for its native ISA. SASSI is a pass in NVIDIA's backend compiler, ptxas, that selectively inserts instrumentation code. The purpose of SASSI is to allow users to measure or modify ptxas-generated SASS by injecting instrumentation code during code generation.
NVIDIA has many excellent development tools. Why the need for another tool? NVIDIA's tools such as cuda-memcheck and nvvp provide excellent, but fixed-function inspection of programs. While they are great at what they are designed for, the user has to choose from a fixed menu of program characteristics to measure. If you want to measure some aspect of program execution outside the purview of those tools you are out of luck. SASSI allows users to flexibly inject their own instrumentation to measure novel aspects of GPGPU execution.
SASSI consists of two main components:
We have added some new features. There is a new instrumentation
library that demonstrates how to map a SASS instruction with a given
PUPC (SASSI's version of a PC) to the CUDA source. See the “branch”
library for its usage. Also see the branch target in
example/Makefile for the compiler flags necessary to use the new
feature.
Support for emulating novel SASS instructions for ISA exploration is more stable. We have not yet documented this feature because we are still working out the kinks, but if you are interested in this feature, please contact me.
Bug fix. The PUPC was invalid for functions with long names. This fix requires installing the latest SASSI binaries.
SASSI has the following system prerequisites:
nvidia-smi
command.After you have fulfilled your prerequisites, install SASSI by doing the following:
sh, for example, sh SASSI_x86_64_centos_6.run.You might need to run the installer as root, depending on where you plan to install SASSI.
For usage, please follow the instructions in the user guide, which you
can find in doc/sassi-user-guide.pdf.
Additionally, ptxas -h lists SASSI's supported options.
32-bit architectures are not supported.
This was an early design decision to reduce the large cross product of possible configurations. Please let us know if 32-bit support would be useful though, because it probably wouldn't be too hard to support.
Programs currently have to be compiled with -rdc=true, which
affects performance.
SASSI allows users to instrument code by injecting function calls to
user-defined functions that are later linked in. In order to perform
cross-module function calls in CUDA one must use the “relocatable
device code” option, -rdc=true. Future versions of SASSI may remove
this restriction.
Minimum driver required is 346.41.
This version of SASSI is designed to work with the CUDA 7 toolchain, which also has that requirement.