The attached patch implements fsys_getcpu which is fast system call implementation for getcpu system call. The patch is against linux-2.6.20. It needs to apply getcpu system call patch first. The getcpu system call patch can be found at: http://www.gelato.unsw.edu.au/archives/linux-ia64/0702/19940.html On 1.6GHz Montectio Tiger4, the following performance data is measured with kernel built with defconfig which has NUMA configured: Fastest sys_getcpu: 502 itc counts. Fastest fsys_getcpu: 28 itc counts. fsys_getcpu performance is largly impacted by whether data (node_to_cpu_map etc) is in cache. It can take fsys_getcpu up to ~150 itc counts in cold cache case. Thanks. -Fenghua Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx> --- linux-2.6.git.orig/arch/ia64/kernel/fsys.S 2006-11-29 12:26:02.000000000 -0800 +++ linux-2.6.git/arch/ia64/kernel/fsys.S 2007-02-09 08:55:53.000000000 -0800 @@ -10,6 +10,8 @@ * probably broke it along the way... ;-) * 13-Jul-04 clameter Implement fsys_clock_gettime and revise fsys_gettimeofday to make * it capable of using memory based clocks without falling back to C code. + * 08-Feb-07 Fenghua Yu Implement fsys_getcpu. + * */ #include <asm/asmmacro.h> @@ -505,6 +507,59 @@ EX(.fail_efault, (p15) st8 [r34]=r3) #endif END(fsys_rt_sigprocmask) +/* + * fsys_getcpu doesn't use the third parameter in this implementation. It reads + * current_thread_info()->cpu and corresponding node in cpu_to_node_map. + */ +ENTRY(fsys_getcpu) + .prologue + .altrp b6 + .body + ;; + add r2=TI_FLAGS+IA64_TASK_SIZE,r16 + tnat.nz p6,p0 = r32 // guard against NaT argument + add r3=TI_CPU+IA64_TASK_SIZE,r16 + ;; + ld4 r3=[r3] // M r3 = thread_info->cpu + ld4 r2=[r2] // M r2 = thread_info->flags +(p6) br.cond.spnt.few .fail_einval // B + ;; + tnat.nz p7,p0 = r33 // I guard against NaT argument +(p7) br.cond.spnt.few .fail_einval // B +#ifdef CONFIG_NUMA + movl r17=cpu_to_node_map + ;; +EX(.fail_efault, probe.w.fault r32, 3) // M This takes 5 cycles +EX(.fail_efault, probe.w.fault r33, 3) // M This takes 5 cycles + shladd r18=r3,1,r17 + ;; + ld2 r20=[r18] // r20 = cpu_to_node_map[cpu] + and r2 = TIF_ALLWORK_MASK,r2 + ;; + cmp.ne p8,p0=0,r2 +(p8) br.spnt.many fsys_fallback_syscall + ;; + ;; +EX(.fail_efault, st4 [r32] = r3) +EX(.fail_efault, st2 [r33] = r20) + mov r8=0 + ;; +#else +EX(.fail_efault, probe.w.fault r32, 3) // M This takes 5 cycles +EX(.fail_efault, probe.w.fault r33, 3) // M This takes 5 cycles + and r2 = TIF_ALLWORK_MASK,r2 + ;; + cmp.ne p8,p0=0,r2 +(p8) br.spnt.many fsys_fallback_syscall + ;; +EX(.fail_efault, st4 [r32] = r3) +EX(.fail_efault, st2 [r33] = r0) + mov r8=0 + ;; +#endif + FSYS_RETURN +END(fsys_getcpu) + ENTRY(fsys_fallback_syscall) .prologue .altrp b6 @@ -878,6 +933,56 @@ fsyscall_table: data8 0 // timer_delete data8 0 // clock_settime data8 fsys_clock_gettime // clock_gettime + data8 0 // clock_getres // 1255 + data8 0 // clock_nanosleep + data8 0 // fstatfs64 + data8 0 // statfs64 + data8 0 // mbind + data8 0 // get_mempolicy // 1260 + data8 0 // set_mempolicy + data8 0 // mq_open + data8 0 // mq_unlink + data8 0 // mq_timedsend + data8 0 // mq_timedreceive // 1265 + data8 0 // mq_notify + data8 0 // mq_getsetattr + data8 0 // kexec_load + data8 0 // vserver + data8 0 // waitid // 1270 + data8 0 // add_key + data8 0 // request_key + data8 0 // keyctl + data8 0 // ioprio_set + data8 0 // ioprio_get // 1275 + data8 0 // move_pages + data8 0 // inotify_init + data8 0 // inotify_add_watch + data8 0 // inotify_rm_watch + data8 0 // migrate_pages // 1280 + data8 0 // openat + data8 0 // mkdirat + data8 0 // mknodat + data8 0 // fchownat + data8 0 // futimesat // 1285 + data8 0 // newfstatat + data8 0 // unlinkat + data8 0 // renameat + data8 0 // linkat + data8 0 // symlinkat // 1290 + data8 0 // readlinkat + data8 0 // fchmodat + data8 0 // faccessat + data8 0 + data8 0 // 1295 + data8 0 // unshare + data8 0 // splice + data8 0 // set_robust_list + data8 0 // get_robust_list + data8 0 // sync_file_range // 1300 + data8 0 // tee + data8 0 // vmsplice + data8 0 + data8 fsys_getcpu // getcpu // 1304 // fill in zeros for the remaining entries .zero: --- linux-2.6.git.orig/arch/ia64/kernel/asm-offsets.c 2006-11-29 12:26:02.000000000 -0800 +++ linux-2.6.git/arch/ia64/kernel/asm-offsets.c 2007-02-09 07:20:26.000000000 -0800 @@ -35,6 +35,7 @@ void foo(void) BLANK(); DEFINE(TI_FLAGS, offsetof(struct thread_info, flags)); + DEFINE(TI_CPU, offsetof(struct thread_info, cpu)); DEFINE(TI_PRE_COUNT, offsetof(struct thread_info, preempt_count)); BLANK(); - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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