Linux Kernel https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=stable%2F2.6.16.y 2002-10-31T12:09:56Z 2002-10-31T12:09:56Z Andrew Morton akpm@digeo.com 2002-10-31T12:09:56Z urn:sha1:bb468c02496de13352bd607ff91fab1207edf01f Patch from Mingming, Rusty, Hugh, Dipankar, me: - It greatly reduces the lock contention by having one lock per id. The global spinlock is removed and a spinlock is added in kern_ipc_perm structure. - Uses ReadCopyUpdate in grow_ary() for locking-free resizing. - In the places where ipc_rmid() is called, delay calling ipc_free() to RCU callbacks. This is to prevent ipc_lock() returning an invalid pointer after ipc_rmid(). In addition, use the workqueue to enable RCU freeing vmalloced entries. Also some other changes: - Remove redundant ipc_lockall/ipc_unlockall - Now ipc_unlock() directly takes IPC ID pointer as argument, avoid extra looking up the array. The changes are made based on the input from Huge Dickens, Manfred Spraul and Dipankar Sarma. In addition, Cliff White has run OSDL's dbt1 test on a 2 way against the earlier version of this patch. Results shows about 2-6% improvement on the average number of transactions per second. Here is the summary of his tests: 2.5.42-mm2 2.5.42-mm2-ipclock ----------------------------- Average over 5 runs 85.0 BT 89.8 BT Std Deviation 5 runs 7.4 BT 1.0 BT Average over 4 best 88.15 BT 90.2 BT Std Deviation 4 best 2.8 BT 0.5 BT Also, another test today from Bill Hartner: I tested Mingming's RCU ipc lock patch using a *new* microbenchmark - semopbench. semopbench was written to test the performance of Mingming's patch. I also ran a 3 hour stress and it completed successfully. Explanation of the microbenchmark is below the results. Here is a link to the microbenchmark source. http://www-124.ibm.com/developerworks/opensource/linuxperf/semopbench/semopbench.c SUT : 8-way 700 Mhz PIII I tested 2.5.44-mm2 and 2.5.44-mm2 + RCU ipc patch >semopbench -g 64 -s 16 -n 16384 -r > sem.results.out >readprofile -m /boot/System.map | sort -n +0 -r > sem.profile.out The metric is seconds / per repetition. Lower is better. kernel run 1 run 2 seconds seconds ================== ======= ======= 2.5.44-mm2 515.1 515.4 2.5.44-mm2+rcu-ipc 46.7 46.7 With Mingming's patch, the test completes 10X faster. 2002-10-08T07:10:38Z Stephen D. Smalley sds@tislabs.com 2002-10-08T07:10:38Z urn:sha1:f9274840e891fe6567548cf3eda1ad9d7eda87ed The patch below adds the base set of LSM hooks for System V IPC to the 2.5.41 kernel. These hooks permit a security module to label semaphore sets, message queues, and shared memory segments and to perform security checks on these objects that parallel the existing IPC access checks. Additional LSM hooks for labeling and controlling individual messages sent on a single message queue and for providing fine-grained distinctions among IPC operations will be submitted separately after this base set of LSM IPC hooks has been accepted. 2002-02-05T01:40:40Z Linus Torvalds torvalds@athlon.transmeta.com 2002-02-05T01:40:40Z urn:sha1:7a2deb32924142696b8174cdf9b38cd72a11fc96