This is the opencourse implementation of BaM system (ASPLOS'23). Contributions to the codebase are most welcome
Graphics Processing Units (GPUs) have traditionally relied on the CPU to orchestrate access to data storage. This approach is well-suited for GPU applications with known data access patterns that enable partitioning their data sets to be processed in a pipelined fashion in the GPU. However, many emerging applications, such as graph and data analytics, recommender systems, or graph neural networks, require fine-grained, data-dependent access to storage. CPU orchestration of storage access is unsuitable for these applications due to high CPU-GPU synchronization overheads, I/O traffic amplification, and long CPU processing latencies. GPU self-orchestrated storage access avoids these overheads by removing the CPU from the storage control path and, thus, can potentially support these applications at a much higher speed. However, there is a lack of systems architecture and software stack that enables efficient self-orchestrated storage access by the GPUs.
In this work, we present a novel system architecture, BaM, that offers mechanisms for GPU code to efficiently access storage and enables GPU self-orchestrated storage access. BaM features a fine-grained software cache to coalesce data storage requests while minimizing I/O amplification effects. This software cache communicates with the storage system through high-throughput queues that enable the massive number of concurrent threads in modern GPUs to generate I/O requests at a high-enough rate to fully utilize the storage devices, and the system interconnect. Experimental results show that GPU self-orchestrated storage access running on BaM delivers 1.0$\times$ and 1.49$\times$ end-to-end speed up for BFS and CC graph analytics benchmarks while reducing hardware costs by up to 21.7$\times$. Our experiments also show GPU self-orchestrated storage access speeds up data-analytics workloads by 5.3$\times$ when running on the same hardware.
This code base requires specific type of hardware and specific system configuration to be functional and performant.
- A x86 system supporting PCIe P2P
- A NVMe SSD. Any NVMe SSD will do.
- Please make sure there isn't any needed data on this SSD as the system can write data to the SSD if the application requests to.
- A NVIDIA Tesla/Datacenter grade GPU that is from the Volta or newer generation. A Tesla V100/A100/H100 fit both of these requirements
- A Tesla grade GPU is needed as it can expose all of its memory for P2P accesses over PCIe. (NVIDIA Tesla T4 does not work as it only provides 256M of BAR space)
- A Volta or newer generation of GPU is needed as we rely on memory synchronization primitives only supported since Volta.
- A system that can support
Above 4G Decodingfor PCIe devices.- This is needed to address more than 4GB of memory for PCIe devices, specifically GPU memory.
- This is a feature that might need to be ENABLED in the BIOS of the system.
- For high throughput implementation, we recommend using a PCIe switch to connect the GPU and SSDs in your server. Going over IOMMU degrades performance.
- As mentioned above,
Above 4G Decodingneeds to be ENABLED in the BIOS - The system's IOMMU should be disabled for ease of debugging.
- In Intel Systems, this requires disabling
Vt-din the BIOS - In AMD Systems, this requires disabling
IOMMUin the BIOS
- In Intel Systems, this requires disabling
- The
iommusupport in Linux must be disabled too, which can be checked and disabled following the instructions below. - In the system's BIOS,
ACSmust be disabled if the option is available - Relatively new Linux kernel (ie. 5.x).
- CMake 3.10 or newer and the FindCUDA package for CMake
- GCC version 5.4.0 or newer. Compiler must support C++11 and POSIX threads.
- CUDA 12.3 or newer
- Nvidia driver (at least 440.33 or newer)
- The kernel version we have tested is 5.8.x. A newer kernel like 6.x may not work with BaM as the kernel APIs have dramatically changed.
- Kernel module symbols and headers for the Nvidia driver. The instructions for how to compile these symbols are given below.
If you are using CUDA or implementing support for your own custom devices, you need to explicitly disable IOMMU as IOMMU support for peer-to-peer on Linux is a bit flaky at the moment. If you are not relying on peer-to-peer, we would in fact recommend you leaving the IOMMU on for protecting memory from rogue writes.
To check if the IOMMU is on, you can do the following:
$ cat /proc/cmdline | grep iommu
If either iommu=on or intel_iommu=on is found by grep, the IOMMU
is enabled.
You can disable it by removing iommu=on and intel_iommu=on from the
CMDLINE variable in /etc/default/grub and then reconfiguring GRUB.
The next time you reboot, the IOMMU will be disabled.
Typically the Nvidia driver kernel sources are installed in the /usr/src/ directory.
So if the Nvidia driver version is 470.141.03, then they will be in the /usr/src/nvidia-470.141.03 directory.
So assuming the driver version is 470.141.03, to get the kernel symbols you need to do the following commands as the root user.
$ cd /usr/src/nvidia-470.141.03/
$ sudo make
From the project root directory, do the following:
$ git submodule update --init --recursive
$ mkdir -p build; cd build
$ cmake ..
$ make libnvm # builds library
$ make benchmarks # builds benchmark program
The CMake configuration is supposed to autodetect the location of CUDA,
Nvidia driver and project library. CUDA is located by the FindCUDA package for
CMake, while the location of both the Nvidia driver can be manually
set by overriding the NVIDIA defines for CMake
(cmake .. -DNVIDIA=/usr/src/nvidia-470.141.03/).
After this, you should also compile the custom libnvm kernel module for NVMe devices.
Assuming you are in the root project directory, run the following:
$ cd build/module
$ make
In order to be able to use the custom kernel module for the NVMe device, we need to first unbind
the NVMe device from the default Linux NVMe driver.
To do this, we need to find the PCI ID of the NVMe device.
To find this we can use the kernel log. For example, if the required NVMe device want is mapped to the /dev/nvme0 block device, we can do the following to find the PCI ID.
$ dmesg | grep nvme0
[ 126.497670] nvme nvme0: pci function 0000:65:00.0
[ 126.715023] nvme nvme0: 40/0/0 default/read/poll queues
[ 126.720783] nvme0n1: p1
[ 190.369341] EXT4-fs (nvme0n1p1): mounted filesystem with ordered data mode. Opts: (null)
The first line gives the PCI ID for the /dev/nvme0 device as 0000:65:00.0.
To unbind the NVMe driver for this device we need to do the following as the root user:
# echo -n "0000:65:00.0" > /sys/bus/pci/devices/0000\:65\:00.0/driver/unbind
Please do this for each NVMe device you want to use with this system.
Now we can load the custom kernel module from the root project directory with the following:
$ cd build/module
$ sudo make load
This should create a /dev/libnvm* device file for each controller that isn't bound to the NVMe driver.
The module can be unloaded from the project root directory with the following:
$ cd build/module
$ sudo make unload
The module can be reloaded (unloaded and then loaded) from the project root directory with the following:
$ cd build/module
$ sudo make reload
The fio like benchmark application is compiled as ./bin/nvm-block-bench binary in the build directory.
It basically assigns NVMe block IDs (randomly or sequentially) to each GPU thread and then a GPU kernel is launched in which the GPU threads make the appropriate IO requests.
When multiple NVMe devices are available, the threads (in group of 32) self-assign a SSD in round-robin fashion, so we get uniform distribution of requests to the NVMe devices.
The application must be run with sudo as it needs direct access to the /dev/libnvm* files.
The application arguments are as follows:
$ ./bin/nvm-block-bench --help
OPTION TYPE DEFAULT DESCRIPTION
page_size count 4096 size of each IO request
blk_size count 64 CUDA thread block size
queue_depth count 16 queue depth per queue
num_blks count 2097152 number of pages in backing array
input path Input dataset path used to write to NVMe SSD
gpu number 0 specify CUDA device
n_ctrls number 1 specify number of NVMe controllers
reqs count 1 number of reqs per thread
access_type count 0 type of access to make: 0->read, 1->write, 2->mixed
pages count 1024 number of pages in cache
num_queues count 1 number of queues per controller
random bool true if true the random access benchmark runs, if false the sequential access benchmark runs
ratio count 100 ratio split for % of mixed accesses that are read
threads count 1024 number of CUDA threads
The application prints many things during initalization as it helps in debugging, however near the end it prints some statistics of the GPU kernel, as shown below:
Elapsed Time: 169567 Number of Ops: 262144 Data Size (bytes): 134217728
Ops/sec: 1.54596e+06 Effective Bandwidth(GB/S): 0.73717
If you want to run a large GPU kernel on GPU 5 with many threads (262144 threads grouped into GPU block size of 64) each making 1 random request to the first 2097152 NVME blocks, an NVMe IO read size of 512 bytes (page_size), 128 NVMe queues each 1024 elements deep, you would run the following command:
sudo ./bin/nvm-block-bench --threads=262144 --blk_size=64 --reqs=1 --pages=262144 --queue_depth=1024 --page_size=512 --num_blks=2097152 --gpu=0 --n_ctrls=1 --num_queues=128 --random=true
If you want to run the same benchmark but now with each thread accessing the array sequentially, you would run the following command:
sudo ./bin/nvm-block-bench --threads=262144 --blk_size=64 --reqs=1 --pages=262144 --queue_depth=1024 --page_size=512 --num_blks=2097152 --gpu=0 --n_ctrls=1 --num_queues=128 --random=false
Disclaimer: The NVMe SSD I was using supports 128 queues each with 1024 depth. However, even if your SSD supports less number of queues and/or less depth the system will automatically use the numbers reported by your device if you specify larger numbers.
BaM is evaluated on several applications and datasets. A limited set of them are released to public in benchmarks folder. Other applications, e.g. data analytics, are proprietary.
Microbenchmarks Several microbenchmarks are provided in benchmarks folder. array benchmark evaluated the performance of array abstraction with the BaM cache and access to SSDs on misses, block benchmark is akin to fio and evaluates the performance of BaM I/O stack. cache and pattern benchmark evaluates the performance of BaM cache across different access patterns. readwrite benchmarks evaluates the reading and writing very large datasets to single SSDs (multiple SSD write is not enabled in the application despite BaM supporting it).
VectorAdd, Scan and Reduction These benchmarks test the performance of extremely large operations on array for given compute primitives. Dataset is randomly generated as these applications are not data-dependent.
Graph Benchmarks Initial implementation of graph benchmarks are taken from EMOGI (https://github.com/illinois-impact/EMOGI). We use the same dataset used in EMOGI and write them into SSDs using benchmark/readwrite application. BFS, CC, SSSP and PageRank benchmarks are implemented. BFS and CC workloads are extensively studied while SSSP and PageRank studies in progress.
Dataset If you need access to these preprocessed datasets, please reach out to us. These are gigantic datasets and we can figure out how to share the preprocessed ones.
Your application One can use any of these example benchmark and implement their application using bam::array abstraction. Feel free to reach out over Github issues incase if you run into issue or require additional insights on how to best use BaM in your codebase.
FOR ASPLOS AOE: PLEASE REFER TO THE asplosaoe DIRECTORY FOR HOW TO RUN THE APPLICATIONS AND THE EXPECTED OUTPUTS!
If you use BaM or concepts or derviate codebase of BaM in your work, please cite the following articles.
@inproceedings{bamasplos,
author = {Qureshi, Zaid and Mailthody, Vikram Sharma and Gelado, Isaac and Min, Seung Won and Masood, Amna and Park, Jeongmin and Xiong, Jinjun and Newburn, CJ and Vainbrand, Dmitri and Chung, I-Hsin and Garland, Michael and Dally, William and Hwu, Wen-mei},
title = {GPU-Initiated On-Demand High-Throughput Storage Access in the BaM System Architecture},
year = {2023},
booktitle = {Proceedings of the Twenty-Eigth International Conference on Architectural Support for Programming Languages and Operating Systems},
series = {ASPLOS '23}
}
@phdthesis{phdthesis1,
title={Infrastructure to Enable and Exploit GPU Orchestrated High-Throughput Storage Access on GPUs},
author={Qureshi, Zaid},
year={2022},
school={University of Illinois Urbana-Champaign}
}
@phdthesis{phdthesis2,
title={Application Support And Adaptation For High-throughput Accelerator Orchestrated Fine-grain Storage Access},
author={Mailthody, Vikram Sharma},
year={2022},
school={University of Illinois Urbana-Champaign}
}
The codebase builds on top of a opensource codebase by Jonas Markussen available here. We take his codebase and make it more robust by adding more error checking and fixing issues of memory alignment along with increasing the performance when large number of requests are available.
We add to the codebase functionality allowing any GPU thread independently access any location on the NVMe device. To facilitate this we develop high-throughput concurrent queues.
Furthermore, we add the support for an application to use multiple NVMe SSDs.
Finally, to lessen the programmer's burden we develop abstractions, like an array abstraction
and a data caching layer, so that the programmer writes their GPU code like they are trained to and the library automatically checks
if accesses hit in the cache or not and if they miss to automatically fetch the needed data from the NVMe device.
All of these features are developed into a header-only library in the include directory.
These headers can be used in Cuda C/C++ application code.
Please check the Contribution.md file for more details.
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