From 73e75b416ffcfa3a84952d8e389a0eca080f00e1 Mon Sep 17 00:00:00 2001 From: Hollis Blanchard Date: Tue, 2 Dec 2008 15:51:57 -0600 Subject: KVM: ppc: Implement in-kernel exit timing statistics Existing KVM statistics are either just counters (kvm_stat) reported for KVM generally or trace based aproaches like kvm_trace. For KVM on powerpc we had the need to track the timings of the different exit types. While this could be achieved parsing data created with a kvm_trace extension this adds too much overhead (at least on embedded PowerPC) slowing down the workloads we wanted to measure. Therefore this patch adds a in-kernel exit timing statistic to the powerpc kvm code. These statistic is available per vm&vcpu under the kvm debugfs directory. As this statistic is low, but still some overhead it can be enabled via a .config entry and should be off by default. Since this patch touched all powerpc kvm_stat code anyway this code is now merged and simplified together with the exit timing statistic code (still working with exit timing disabled in .config). Signed-off-by: Christian Ehrhardt Signed-off-by: Hollis Blanchard Signed-off-by: Avi Kivity --- arch/powerpc/kvm/timing.c | 262 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 262 insertions(+) create mode 100644 arch/powerpc/kvm/timing.c (limited to 'arch/powerpc/kvm/timing.c') diff --git a/arch/powerpc/kvm/timing.c b/arch/powerpc/kvm/timing.c new file mode 100644 index 00000000000..f42d2728a6a --- /dev/null +++ b/arch/powerpc/kvm/timing.c @@ -0,0 +1,262 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License, version 2, as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * Copyright IBM Corp. 2007 + * + * Authors: Hollis Blanchard + * Christian Ehrhardt + */ + +#include +#include +#include +#include +#include + +#include "timing.h" +#include +#include + +void kvmppc_init_timing_stats(struct kvm_vcpu *vcpu) +{ + int i; + + /* pause guest execution to avoid concurrent updates */ + local_irq_disable(); + mutex_lock(&vcpu->mutex); + + vcpu->arch.last_exit_type = 0xDEAD; + for (i = 0; i < __NUMBER_OF_KVM_EXIT_TYPES; i++) { + vcpu->arch.timing_count_type[i] = 0; + vcpu->arch.timing_max_duration[i] = 0; + vcpu->arch.timing_min_duration[i] = 0xFFFFFFFF; + vcpu->arch.timing_sum_duration[i] = 0; + vcpu->arch.timing_sum_quad_duration[i] = 0; + } + vcpu->arch.timing_last_exit = 0; + vcpu->arch.timing_exit.tv64 = 0; + vcpu->arch.timing_last_enter.tv64 = 0; + + mutex_unlock(&vcpu->mutex); + local_irq_enable(); +} + +static void add_exit_timing(struct kvm_vcpu *vcpu, + u64 duration, int type) +{ + u64 old; + + do_div(duration, tb_ticks_per_usec); + if (unlikely(duration > 0xFFFFFFFF)) { + printk(KERN_ERR"%s - duration too big -> overflow" + " duration %lld type %d exit #%d\n", + __func__, duration, type, + vcpu->arch.timing_count_type[type]); + return; + } + + vcpu->arch.timing_count_type[type]++; + + /* sum */ + old = vcpu->arch.timing_sum_duration[type]; + vcpu->arch.timing_sum_duration[type] += duration; + if (unlikely(old > vcpu->arch.timing_sum_duration[type])) { + printk(KERN_ERR"%s - wrap adding sum of durations" + " old %lld new %lld type %d exit # of type %d\n", + __func__, old, vcpu->arch.timing_sum_duration[type], + type, vcpu->arch.timing_count_type[type]); + } + + /* square sum */ + old = vcpu->arch.timing_sum_quad_duration[type]; + vcpu->arch.timing_sum_quad_duration[type] += (duration*duration); + if (unlikely(old > vcpu->arch.timing_sum_quad_duration[type])) { + printk(KERN_ERR"%s - wrap adding sum of squared durations" + " old %lld new %lld type %d exit # of type %d\n", + __func__, old, + vcpu->arch.timing_sum_quad_duration[type], + type, vcpu->arch.timing_count_type[type]); + } + + /* set min/max */ + if (unlikely(duration < vcpu->arch.timing_min_duration[type])) + vcpu->arch.timing_min_duration[type] = duration; + if (unlikely(duration > vcpu->arch.timing_max_duration[type])) + vcpu->arch.timing_max_duration[type] = duration; +} + +void kvmppc_update_timing_stats(struct kvm_vcpu *vcpu) +{ + u64 exit = vcpu->arch.timing_last_exit; + u64 enter = vcpu->arch.timing_last_enter.tv64; + + /* save exit time, used next exit when the reenter time is known */ + vcpu->arch.timing_last_exit = vcpu->arch.timing_exit.tv64; + + if (unlikely(vcpu->arch.last_exit_type == 0xDEAD || exit == 0)) + return; /* skip incomplete cycle (e.g. after reset) */ + + /* update statistics for average and standard deviation */ + add_exit_timing(vcpu, (enter - exit), vcpu->arch.last_exit_type); + /* enter -> timing_last_exit is time spent in guest - log this too */ + add_exit_timing(vcpu, (vcpu->arch.timing_last_exit - enter), + TIMEINGUEST); +} + +static const char *kvm_exit_names[__NUMBER_OF_KVM_EXIT_TYPES] = { + [MMIO_EXITS] = "MMIO", + [DCR_EXITS] = "DCR", + [SIGNAL_EXITS] = "SIGNAL", + [ITLB_REAL_MISS_EXITS] = "ITLBREAL", + [ITLB_VIRT_MISS_EXITS] = "ITLBVIRT", + [DTLB_REAL_MISS_EXITS] = "DTLBREAL", + [DTLB_VIRT_MISS_EXITS] = "DTLBVIRT", + [SYSCALL_EXITS] = "SYSCALL", + [ISI_EXITS] = "ISI", + [DSI_EXITS] = "DSI", + [EMULATED_INST_EXITS] = "EMULINST", + [EMULATED_MTMSRWE_EXITS] = "EMUL_WAIT", + [EMULATED_WRTEE_EXITS] = "EMUL_WRTEE", + [EMULATED_MTSPR_EXITS] = "EMUL_MTSPR", + [EMULATED_MFSPR_EXITS] = "EMUL_MFSPR", + [EMULATED_MTMSR_EXITS] = "EMUL_MTMSR", + [EMULATED_MFMSR_EXITS] = "EMUL_MFMSR", + [EMULATED_TLBSX_EXITS] = "EMUL_TLBSX", + [EMULATED_TLBWE_EXITS] = "EMUL_TLBWE", + [EMULATED_RFI_EXITS] = "EMUL_RFI", + [DEC_EXITS] = "DEC", + [EXT_INTR_EXITS] = "EXTINT", + [HALT_WAKEUP] = "HALT", + [USR_PR_INST] = "USR_PR_INST", + [FP_UNAVAIL] = "FP_UNAVAIL", + [DEBUG_EXITS] = "DEBUG", + [TIMEINGUEST] = "TIMEINGUEST" +}; + +static int kvmppc_exit_timing_show(struct seq_file *m, void *private) +{ + struct kvm_vcpu *vcpu = m->private; + int i; + u64 min, max; + + for (i = 0; i < __NUMBER_OF_KVM_EXIT_TYPES; i++) { + if (vcpu->arch.timing_min_duration[i] == 0xFFFFFFFF) + min = 0; + else + min = vcpu->arch.timing_min_duration[i]; + if (vcpu->arch.timing_max_duration[i] == 0) + max = 0; + else + max = vcpu->arch.timing_max_duration[i]; + + seq_printf(m, "%12s: count %10d min %10lld " + "max %10lld sum %20lld sum_quad %20lld\n", + kvm_exit_names[i], vcpu->arch.timing_count_type[i], + vcpu->arch.timing_min_duration[i], + vcpu->arch.timing_max_duration[i], + vcpu->arch.timing_sum_duration[i], + vcpu->arch.timing_sum_quad_duration[i]); + } + return 0; +} + +static ssize_t kvmppc_exit_timing_write(struct file *file, + const char __user *user_buf, + size_t count, loff_t *ppos) +{ + size_t len; + int err; + const char __user *p; + char c; + + len = 0; + p = user_buf; + while (len < count) { + if (get_user(c, p++)) + err = -EFAULT; + if (c == 0 || c == '\n') + break; + len++; + } + + if (len > 1) { + err = -EINVAL; + goto done; + } + + if (copy_from_user(&c, user_buf, sizeof(c))) { + err = -EFAULT; + goto done; + } + + if (c == 'c') { + struct seq_file *seqf = (struct seq_file *)file->private_data; + struct kvm_vcpu *vcpu = seqf->private; + /* write does not affect out buffers previsously generated with + * show. Seq file is locked here to prevent races of init with + * a show call */ + mutex_lock(&seqf->lock); + kvmppc_init_timing_stats(vcpu); + mutex_unlock(&seqf->lock); + err = count; + } else { + err = -EINVAL; + goto done; + } + +done: + return err; +} + +static int kvmppc_exit_timing_open(struct inode *inode, struct file *file) +{ + return single_open(file, kvmppc_exit_timing_show, inode->i_private); +} + +static struct file_operations kvmppc_exit_timing_fops = { + .owner = THIS_MODULE, + .open = kvmppc_exit_timing_open, + .read = seq_read, + .write = kvmppc_exit_timing_write, + .llseek = seq_lseek, + .release = single_release, +}; + +void kvmppc_create_vcpu_debugfs(struct kvm_vcpu *vcpu, unsigned int id) +{ + static char dbg_fname[50]; + struct dentry *debugfs_file; + + snprintf(dbg_fname, sizeof(dbg_fname), "vm%u_vcpu%03u_timing", + current->pid, id); + debugfs_file = debugfs_create_file(dbg_fname, 0666, + kvm_debugfs_dir, vcpu, + &kvmppc_exit_timing_fops); + + if (!debugfs_file) { + printk(KERN_ERR"%s: error creating debugfs file %s\n", + __func__, dbg_fname); + return; + } + + vcpu->arch.debugfs_exit_timing = debugfs_file; +} + +void kvmppc_remove_vcpu_debugfs(struct kvm_vcpu *vcpu) +{ + if (vcpu->arch.debugfs_exit_timing) { + debugfs_remove(vcpu->arch.debugfs_exit_timing); + vcpu->arch.debugfs_exit_timing = NULL; + } +} -- cgit v1.2.3