compudj

5 ms·

1.
New Microsoft Tools for Analyzing Android, Linux, Chromium Browser Performance(devblogs.microsoft.com)
16 points by compudj 5y ago|0 comments
2.
LTTng 2.13 facilitates quick reaction to kernel/user-space instrumentation hit(lists.lttng.org)
28 points by compudj 5y ago|2 comments
3.
by compudj 8y ago
GPLv2 provides implicit patent grant in section 6 and section 7. LGPLv2.1 has basically the same content in section 10 and section 11. IANAL, but AFAIU LGPLv2.1 provides implicit patent grant in the same way as GPLv2. IBM has allowed use of
4.
by compudj 8y ago
IBM allowed their RCU contribution to be used in LGPLv2 or later code through this commit they kindly contributed to the Userspace RCU project: commit 54843abcc17c8e8b7600ed635e966c6970d8d20f Author: Paul E. McKenney <paulmck@linux
5.
by compudj 8y ago
I've been in touch with FB. They are interested in using rseq for jemalloc. They have provided prototypes of jemalloc based on rseq, along with benchmarks helping me make the case for rseq mainlining. I don't know whether Google w
6.
by compudj 8y ago
Sure, before getting it upstream, I had to: - Gather a list of desiderata, ensuring we take into account a complete list of use-cases targeted by everyone active in the rseq discussions. This is crucially important to ensure discussions don
7.
by compudj 8y ago
I'm currently discussing with glibc maintainers on the best approach to integrate this into the Linux userspace ecosystem. So far, discussions aim into a direction where glibc would own the __rseq_abi TLS symbol, and register it for ev
8.
by compudj 8y ago
Yes, there are indeed pieces missing for this use-case. I intend to push another system call for the next merge window (4.19): "cpu_opv" [1]. It stands for "CPU operation vector", which is needed to take care of moving u
9.
by compudj 8y ago
Indeed the restartable sequence critical section needs to be written in assembly. The idea is to keep this complexity within public headers implementing the common operations as inline assembly for all supported architectures. You can see
10.
by compudj 8y ago
It all depends on how much control you have on the system you target. The strategy you refer to may well work for a dedicated deployment, but if you are developing a general-purpose memory allocator targeting a wide range of applications, y
11.
by compudj 8y ago
(disclaimer: I am the patch author, Mathieu Desnoyers) Just as a clarification, the idea originates from Google (I give full credits to Paul Turner and Andrew Hunter for it). However, the extra 3 years of work required to get it upstream ha
12.
by compudj 8y ago
Some use-cases likely to be enhanced by rseq: statistics counters, memory allocators (jemalloc, glibc malloc, and others), user-space tracing (LTTng), user-space Read-Copy Update (liburcu), reading performance monitoring unit counters from
13.
by compudj 8y ago
If you are looking for examples of per-cpu data structures using rseq, see the selftests I implemented here: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin... There are examples o
14.
by compudj 8y ago
Yes, Will Deacon (Linux ARM64 maintainer) is working on it right now.
15.
LTTng Scope 0.3: A basic tutorial(lttng.org)
3 points by compudj 9y ago|0 comments
16.
by compudj 10y ago
Hi Brendan, (Full disclosure: I'm Mathieu Desnoyers, part of the LTTng maintainer team.) I would like to introduce a slightly less extreme point of view when considering "on-the-fly" aggregation of traces vs tracing to buffer
17.
by compudj 10y ago
Currently, LTTng-UST has slightly higher overhead than 100 cycles per event (roughly 250-300 ns/event on recent 2.4GHz Intel), which I expect is partly caused by use of per-CPU buffers rather than per-thread buffers. I have contributed
18.
by compudj 10y ago
I don't see any mention of Intel's errata on cross-modifying code on SMP in the paper. I wonder how the authors handle this ? See "Unsynchronized Cross-Modifying Code Operations Can Cause Unexpected Instruction Execution Resu
19.
by compudj 11y ago
It looks like the authors have not heard about kernel-level page cache. No fsync was ever used in the benchmarks, therefore, it is never actually hitting the disk. The only good thing about this paper is that the Java and Python listings ar