dmemsys / smart Goto Github PK

Hello, in the workload_spec file, using requestdistribution=latest to generate YCSB-D workload, and how to generate uniform YCSB-D? Because YCSB-D's requestdistribution=latest, how do you distinguish whether the YCSB-D is uniformly or zip-fianally distributed?

Hi,

I found that some parts of your code utilize RDMA atomic operations and READ/WRITE on the same memory region. (e.g., The node_type in Header). However, it may harm the correctness of synchronization.
The Infiniband Architecture Specification 1.4 has pointed out in section 10.7.2.3 that it's unsafe to simultaneously use atomic and nonatomic operations on the same memory region.
I believe the reason is that "atomic" is only effective for the NIC execution but not for the flushing through PCIe.
Recent paper SIGMOD'23 Design Guidelines for Correct, Efficient, and Scalable Synchronization using One-Sided RDMA and this QA https://lore.kernel.org/linux-rdma/20200512113512.GK4814@unreal/T/ confirms my point.

Thus, I want to ask: Is it a bug in your code? If it isn't, how did you further ensure the correctness of synchronization?

I encounter an "Server 0 Counld't incr value and get ID: SERVER HAS FAILED AND IS DISABLED UNTIL TIMED RETRY, retry..."when doing the ycsb test. I wonder how to solve this problem.

When I run the YCSB test on my server, "compute server 65535 start up [0.0.0.0]" appears on the terminal, which is the wrong ID and wrong IP ，I wonder what could contribute to this error

When I change the parameter NET_DEV_NAME ，if I change it to the IB network interface like "ib0", it returns the wrong IPv4 address. And when I change it to the Ethernet interface like"eno1" ，the IP address is right but I get the wrong my_node_ID，like if my IP address is 192.168.0.167, "compute server 166 start up" show in the terminal instead of compute server 0. I wonder how I can correctly set this parameter.

Hello,I appreciate your work sincerely. Now I want to run the project on cloudlab and fail to start my project on cloudlab. So can you help me and I earnestly request your assistance in conducting experiments on CloudLab.

Hello, SMART is a great job, and I am interested in it. Could you please tell me how to get sherman's result? I have tried to use "cmake -DSTATIC_MN_IP=on -DENABLE_CACHE=on -DLONG_TEST_EPOCH=off -DSHORT_TEST_EPOCH=off -DMIDDLE_TEST_EPOCH=off -DENABLE_CACHE_EVICTION=off -DON_CHIP=on .." to run sherman, but the result is similar to SMART. How can I get the sheman's result, as the fig18c shows?
Looking forward to your early reply. Thanks a lot!

Hi, Xuchuan
I still don't understand using both read delegation and write combining mechanisms at the same time.

What is the meaning of using the same time window in the paper? My understanding from the code is to extend the write combining time window from the end of the leaf lock to after the leaf unlock, i.e., to include the full tree access process just like search. But how does this mechanism allow causally related write and read operations in two threads to be assigned to two different time windows? The paper points out that the read and write clients compete for the same local lock, and I don't think I've seen any code for that.

Finally, the code uses read/write_window, r/w_lock to keep track of the corresponding time window, and only opens a new window when read/write_window is 0 at the same time (i.e., sets the corresponding read/write_window). In my understanding, a lock node's read_window and write_window can have both read and write to a key occurring at the same time, so there is still a case where causality is not guaranteed. Can you explain in more detail the consistency guarantees provided?

Hello, Tree.cpp doesn't provide the function "Deletion." How can I implement it?

I look forward to your early reply. Thanks a lot!

Hi, Xuchuan

I am working on addressing concurrency issue with the index cache while executing SMART's code. I am using a server with 18 threads, YCSB C, and an all-write workload. The error message indicates:
`==22691==ERROR: AddressSanitizer: heap-use-after-free on address 0x60400017e291 at pc 0x000000560d06 bp 0x7fb089ef7980 sp 0x7fb089ef7978
READ of size 8 at 0x60400017e291 thread T2
==22691==AddressSanitizer: while reporting a bug found another one. Ignoring.
#0 0x560d05 in GADD(GlobalAddress const&, int) /mnt/codes/SMART/include/GlobalAddress.h:40
#1 0x560d05 in Tree::insert(std::array<unsigned char, 8ul> const&, unsigned long, CoroContext*, int, bool, bool) /mnt/codes/SMART/src/Tree.cpp:131
#2 0x524ca4 in thread_run(int) /mnt/codes/SMART/test/ycsb_test.cpp:182
#3 0x7fb38ab209ff (/usr/lib/x86_64-linux-gnu/libstdc++.so.6+0xd09ff)
#4 0x7fb38b4c36b9 in start_thread (/lib/x86_64-linux-gnu/libpthread.so.0+0x76b9)
#5 0x7fb389e6051c in clone (/lib/x86_64-linux-gnu/libc.so.6+0x10751c)

0x60400017e291 is located 1 bytes inside of 40-byte region [0x60400017e290,0x60400017e2b8)
freed by thread T13 here:
#0 0x4ea638 in operator delete(void*, unsigned long) ../../../../gcc-7.5.0/libsanitizer/asan/asan_new_delete.cc:140
#1 0x572bae in RadixCache::_safely_delete(CacheEntry*) /mnt/codes/SMART/src/RadixCache.cpp:357

previously allocated by thread T17 here:
#0 0x4e92b0 in operator new(unsigned long) ../../../../gcc-7.5.0/libsanitizer/asan/asan_new_delete.cc:80
#1 0x57e129 in RadixCache::add_to_cache(std::array<unsigned char, 8ul> const&, InternalPage const*, GlobalAddress const&) /mnt/codes/SMART/src/RadixCache.cpp:25
`

May I ask if you know why this is happening? How can it be fixed?

Thank you!

I wonder how the master node is set up in the experiment. As you say, the IP address of a master node of the r650 cluster is the node which can directly establish SSH connections to other nodes. So how can I make a node that can connect to other nodes in Cloudlab. Is it OK if I just change the master_ip parameter in the code?

Thank you!