Lock-based Protocol Research Articles

Salvage of the peritoneal dialysis catheter in Candida peritonitis using amphotericin B catheter lock.

Candida species form biofilms, facilitating adherence to peritoneal dialysis (PD) catheters and making them less susceptible to antifungal therapy. Therefore, the International Society for Peritoneal Dialysis recommends immediate PD catheter removal in case of Candida peritonitis. However, in 2007, our institution showed that Candida peritonitis could be successfully treated without catheter removal with a treatment strategy including amphotericin B as catheter lock. To confirm the efficacy and safety of this lock-based protocol, we evaluated the outcome of Candida peritonitis episodes since then. A retrospective, single-centre study was conducted in which we analysed all Candida peritonitis episodes in PD patients, treated with the lock-based protocol between July 2006 and March 2018. Eleven non-relapse Candida peritonitis episodes in 10 patients were treated with the lock-based protocol. Seven of the 11 episodes (64%) were cured without PD catheter removal (5 episodes cured immediately, 1 episode cured after an early relapse and 1 episode cured after a late relapse), in 2 episodes (18%) the catheter had to be removed, and two patients died (18%). This study confirms our previous findings that an amphotericin B lock-based protocol has potential to cure Candida peritonitis without PD catheter removal. However, further research is needed given the limitations of this study. Until that time, the lock-based Candida protocol could be used in patients who are not severely ill and in whom PD catheter removal is not desirable.

Energy-Efficient Scheduling of Writers/Readers Problem with Lock-Free Objects

To reduce energy consumption of embedded real-time system with dependent tasks caused by resource sharing, an algorithm called Writer Reader Aware Speed Assignment (WRAS) was proposed to divide tasks into writers and readers and then calculate proper speeds for every writers and readers under the Earliest Deadline First (EDF) policy. The difference from prior work is the using of lock-free and wait-free protocol for synchronization, most prior researches were based on the lock-based protocol. Many simulations have been done to test the proposed algorithm, compared with existing work, WRAS performs better in energy saving, the lowest energy consumption can be get when using wait-free protocol where all tasks execute at the lowest speed.

Synchronization with multiprocessor caches

Introducing private caches in bus-based shared memory multiprocessors leads to the cache consistency problem since there may be multiple copies of shared data. However, the ability to snoop on the bus coupled with the fast broadcast capability allows the design of special hardware support for synchronization. We present a new lock-based cache scheme which incorporates synchronization into the cache coherency mechanism. With this scheme high-level synchronization primitives as well as low-level ones can be implemented without excessive overhead. Cost functions for well-known synchronization methods are derived for invalidation schemes, write update schemes, and our lock-based scheme. To accurately predict the performance implications of the new scheme, a new simulation model is developed embodying a widely accepted paradigm of parallel programming. It is shown that our lock-based protocol outperforms existing cache protocols.