From f7a5f132b447cb6301ab3f0b0468a63db29e41f5 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Fri, 7 Oct 2016 17:02:17 -0700 Subject: [PATCH] proc: faster /proc/*/status top(1) opens the following files for every PID: /proc/*/stat /proc/*/statm /proc/*/status This patch switches /proc/*/status away from seq_printf(). The result is 13.5% speedup. Benchmark is open("/proc/self/status")+read+close 1.000.000 million times. BEFORE $ perf stat -r 10 taskset -c 3 ./proc-self-status Performance counter stats for 'taskset -c 3 ./proc-self-status' (10 runs): 10748.474301 task-clock (msec) # 0.954 CPUs utilized ( +- 0.91% ) 12 context-switches # 0.001 K/sec ( +- 1.09% ) 1 cpu-migrations # 0.000 K/sec 104 page-faults # 0.010 K/sec ( +- 0.45% ) 37,424,127,876 cycles # 3.482 GHz ( +- 0.04% ) 8,453,010,029 stalled-cycles-frontend # 22.59% frontend cycles idle ( +- 0.12% ) 3,747,609,427 stalled-cycles-backend # 10.01% backend cycles idle ( +- 0.68% ) 65,632,764,147 instructions # 1.75 insn per cycle # 0.13 stalled cycles per insn ( +- 0.00% ) 13,981,324,775 branches # 1300.773 M/sec ( +- 0.00% ) 138,967,110 branch-misses # 0.99% of all branches ( +- 0.18% ) 11.263885428 seconds time elapsed ( +- 0.04% ) ^^^^^^^^^^^^ AFTER $ perf stat -r 10 taskset -c 3 ./proc-self-status Performance counter stats for 'taskset -c 3 ./proc-self-status' (10 runs): 9010.521776 task-clock (msec) # 0.925 CPUs utilized ( +- 1.54% ) 11 context-switches # 0.001 K/sec ( +- 1.54% ) 1 cpu-migrations # 0.000 K/sec ( +- 11.11% ) 103 page-faults # 0.011 K/sec ( +- 0.60% ) 32,352,310,603 cycles # 3.591 GHz ( +- 0.07% ) 7,849,199,578 stalled-cycles-frontend # 24.26% frontend cycles idle ( +- 0.27% ) 3,269,738,842 stalled-cycles-backend # 10.11% backend cycles idle ( +- 0.73% ) 56,012,163,567 instructions # 1.73 insn per cycle # 0.14 stalled cycles per insn ( +- 0.00% ) 11,735,778,795 branches # 1302.453 M/sec ( +- 0.00% ) 98,084,459 branch-misses # 0.84% of all branches ( +- 0.28% ) 9.741247736 seconds time elapsed ( +- 0.07% ) ^^^^^^^^^^^ Link: http://lkml.kernel.org/r/20160806125608.GB1187@p183.telecom.by Signed-off-by: Alexey Dobriyan Cc: Joe Perches Cc: Andi Kleen Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/array.c | 85 ++++++++++++++++++++++++++----------------------- 1 file changed, 46 insertions(+), 39 deletions(-) diff --git a/fs/proc/array.c b/fs/proc/array.c index 88c7de12197b..5e7d2521d496 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -186,51 +186,52 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns, task_unlock(p); rcu_read_unlock(); - seq_printf(m, - "State:\t%s\n" - "Tgid:\t%d\n" - "Ngid:\t%d\n" - "Pid:\t%d\n" - "PPid:\t%d\n" - "TracerPid:\t%d\n" - "Uid:\t%d\t%d\t%d\t%d\n" - "Gid:\t%d\t%d\t%d\t%d\n" - "FDSize:\t%d\nGroups:\t", - get_task_state(p), - tgid, ngid, pid_nr_ns(pid, ns), ppid, tpid, - from_kuid_munged(user_ns, cred->uid), - from_kuid_munged(user_ns, cred->euid), - from_kuid_munged(user_ns, cred->suid), - from_kuid_munged(user_ns, cred->fsuid), - from_kgid_munged(user_ns, cred->gid), - from_kgid_munged(user_ns, cred->egid), - from_kgid_munged(user_ns, cred->sgid), - from_kgid_munged(user_ns, cred->fsgid), - max_fds); + seq_printf(m, "State:\t%s", get_task_state(p)); + seq_puts(m, "\nTgid:\t"); + seq_put_decimal_ull(m, 0, tgid); + seq_puts(m, "\nNgid:\t"); + seq_put_decimal_ull(m, 0, ngid); + seq_puts(m, "\nPid:\t"); + seq_put_decimal_ull(m, 0, pid_nr_ns(pid, ns)); + seq_puts(m, "\nPPid:\t"); + seq_put_decimal_ull(m, 0, ppid); + seq_puts(m, "\nTracerPid:\t"); + seq_put_decimal_ull(m, 0, tpid); + seq_puts(m, "\nUid:"); + seq_put_decimal_ull(m, '\t', from_kuid_munged(user_ns, cred->uid)); + seq_put_decimal_ull(m, '\t', from_kuid_munged(user_ns, cred->euid)); + seq_put_decimal_ull(m, '\t', from_kuid_munged(user_ns, cred->suid)); + seq_put_decimal_ull(m, '\t', from_kuid_munged(user_ns, cred->fsuid)); + seq_puts(m, "\nGid:"); + seq_put_decimal_ull(m, '\t', from_kgid_munged(user_ns, cred->gid)); + seq_put_decimal_ull(m, '\t', from_kgid_munged(user_ns, cred->egid)); + seq_put_decimal_ull(m, '\t', from_kgid_munged(user_ns, cred->sgid)); + seq_put_decimal_ull(m, '\t', from_kgid_munged(user_ns, cred->fsgid)); + seq_puts(m, "\nFDSize:\t"); + seq_put_decimal_ull(m, 0, max_fds); + + seq_puts(m, "\nGroups:\t"); group_info = cred->group_info; for (g = 0; g < group_info->ngroups; g++) - seq_printf(m, "%d ", - from_kgid_munged(user_ns, GROUP_AT(group_info, g))); + seq_put_decimal_ull(m, g ? ' ' : 0, from_kgid_munged(user_ns, GROUP_AT(group_info, g))); put_cred(cred); + /* Trailing space shouldn't have been added in the first place. */ + seq_putc(m, ' '); #ifdef CONFIG_PID_NS seq_puts(m, "\nNStgid:"); for (g = ns->level; g <= pid->level; g++) - seq_printf(m, "\t%d", - task_tgid_nr_ns(p, pid->numbers[g].ns)); + seq_put_decimal_ull(m, '\t', task_tgid_nr_ns(p, pid->numbers[g].ns)); seq_puts(m, "\nNSpid:"); for (g = ns->level; g <= pid->level; g++) - seq_printf(m, "\t%d", - task_pid_nr_ns(p, pid->numbers[g].ns)); + seq_put_decimal_ull(m, '\t', task_pid_nr_ns(p, pid->numbers[g].ns)); seq_puts(m, "\nNSpgid:"); for (g = ns->level; g <= pid->level; g++) - seq_printf(m, "\t%d", - task_pgrp_nr_ns(p, pid->numbers[g].ns)); + seq_put_decimal_ull(m, '\t', task_pgrp_nr_ns(p, pid->numbers[g].ns)); seq_puts(m, "\nNSsid:"); for (g = ns->level; g <= pid->level; g++) - seq_printf(m, "\t%d", - task_session_nr_ns(p, pid->numbers[g].ns)); + seq_put_decimal_ull(m, '\t', task_session_nr_ns(p, pid->numbers[g].ns)); #endif seq_putc(m, '\n'); } @@ -299,11 +300,14 @@ static inline void task_sig(struct seq_file *m, struct task_struct *p) unlock_task_sighand(p, &flags); } - seq_printf(m, "Threads:\t%d\n", num_threads); - seq_printf(m, "SigQ:\t%lu/%lu\n", qsize, qlim); + seq_puts(m, "Threads:\t"); + seq_put_decimal_ull(m, 0, num_threads); + seq_puts(m, "\nSigQ:\t"); + seq_put_decimal_ull(m, 0, qsize); + seq_put_decimal_ull(m, '/', qlim); /* render them all */ - render_sigset_t(m, "SigPnd:\t", &pending); + render_sigset_t(m, "\nSigPnd:\t", &pending); render_sigset_t(m, "ShdPnd:\t", &shpending); render_sigset_t(m, "SigBlk:\t", &blocked); render_sigset_t(m, "SigIgn:\t", &ignored); @@ -348,17 +352,20 @@ static inline void task_cap(struct seq_file *m, struct task_struct *p) static inline void task_seccomp(struct seq_file *m, struct task_struct *p) { #ifdef CONFIG_SECCOMP - seq_printf(m, "Seccomp:\t%d\n", p->seccomp.mode); + seq_puts(m, "Seccomp:\t"); + seq_put_decimal_ull(m, 0, p->seccomp.mode); + seq_putc(m, '\n'); #endif } static inline void task_context_switch_counts(struct seq_file *m, struct task_struct *p) { - seq_printf(m, "voluntary_ctxt_switches:\t%lu\n" - "nonvoluntary_ctxt_switches:\t%lu\n", - p->nvcsw, - p->nivcsw); + seq_puts(m, "voluntary_ctxt_switches:\t"); + seq_put_decimal_ull(m, 0, p->nvcsw); + seq_puts(m, "\nnonvoluntary_ctxt_switches:\t"); + seq_put_decimal_ull(m, 0, p->nivcsw); + seq_putc(m, '\n'); } static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)