Messages in this thread | | | Date | Tue, 15 Dec 2009 18:09:04 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | [mmotm][PATCH 0/5] mm rss counting updates |
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This is version 3 or 4....for rss counting. removed RFC.
My purpose is gathering more (rss-related) information per process without scalability impact. (and improve oom-killer etc..) The whole patch series is organized as
[1/5] clean-up per mm stat counting. [2/5] making counter (a bit) more scalable with per-thread counting. [3/5] adding swap counter per mm [4/5] adding lowmem detection logic [5/5] adding lowmem usage counter per mm.
Big changes from previous one are... - removed per-cpu counter. added per-thread counter - synchronization point of a counter is moved to memory.c no hooks to ticks and scheduler.
Now, this patch is not very invasive as previous ones.
cache-miss/page fault with my benchmark on my box is
[Before patch] 4.55 cache-miss/fault [After patch 2] 3.99 cache-miss/fault [After all patch] 4.06 cache-miss/fault
From this numbers, I think swap/lowmem counters can be added.
My test program is attached (this is not modified from previous one)
[Future Plan] - add CONSTRAINT_LOWMEM oom killer. - add rss+swap based oom killer (with sysctl ?) - add some patch for perf ? - add mm_accessor patch. - improve page faults scalability, finally.
Thanks, -Kame /* * multi-fault.c :: causes 60secs of parallel page fault in multi-thread. * % gcc -O2 -o multi-fault multi-fault.c -lpthread * % multi-fault # of cpus. */
#define _GNU_SOURCE #include <stdio.h> #include <pthread.h> #include <sched.h> #include <sys/mman.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <signal.h>
#define CORE_PER_SOCK 4 #define NR_THREADS 8 pthread_t threads[NR_THREADS]; /* * For avoiding contention in page table lock, FAULT area is * sparse. If FAULT_LENGTH is too large for your cpus, decrease it. */ #define MMAP_LENGTH (8 * 1024 * 1024) #define FAULT_LENGTH (2 * 1024 * 1024) void *mmap_area[NR_THREADS]; #define PAGE_SIZE 4096
pthread_barrier_t barrier; int name[NR_THREADS];
void segv_handler(int sig) { sleep(100); } void *worker(void *data) { cpu_set_t set; int cpu;
cpu = *(int *)data;
CPU_ZERO(&set); CPU_SET(cpu, &set); sched_setaffinity(0, sizeof(set), &set);
cpu /= CORE_PER_SOCK;
while (1) { char *c; char *start = mmap_area[cpu]; char *end = mmap_area[cpu] + FAULT_LENGTH; pthread_barrier_wait(&barrier); //printf("fault into %p-%p\n",start, end);
for (c = start; c < end; c += PAGE_SIZE) *c = 0; pthread_barrier_wait(&barrier);
madvise(start, FAULT_LENGTH, MADV_DONTNEED); } return NULL; }
int main(int argc, char *argv[]) { int i, ret; unsigned int num;
if (argc < 2) return 0;
num = atoi(argv[1]); pthread_barrier_init(&barrier, NULL, num);
mmap_area[0] = mmap(NULL, MMAP_LENGTH * num, PROT_WRITE|PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0); for (i = 1; i < num; i++) { mmap_area[i] = mmap_area[i - 1]+ MMAP_LENGTH; }
for (i = 0; i < num; ++i) { name[i] = i * CORE_PER_SOCK; ret = pthread_create(&threads[i], NULL, worker, &name[i]); if (ret < 0) { perror("pthread create"); return 0; } } sleep(60); return 0; }
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