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author | Peter Maydell <peter.maydell@linaro.org> | 2021-02-08 18:23:47 +0000 |
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committer | Peter Maydell <peter.maydell@linaro.org> | 2021-02-08 18:23:47 +0000 |
commit | 2436651b26584c8ebe91db5df67ee054509a0949 (patch) | |
tree | 9f7241de2fb5aa8d82e07433d081fd446250d527 /scripts | |
parent | 4f799257b323e1238a900fd0c71c2057863e0308 (diff) | |
parent | e846b746502e94ce5cb148201ebdaa9c0f658741 (diff) | |
download | qemu-2436651b26584c8ebe91db5df67ee054509a0949.zip qemu-2436651b26584c8ebe91db5df67ee054509a0949.tar.gz qemu-2436651b26584c8ebe91db5df67ee054509a0949.tar.bz2 |
Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20210208a' into staging
Migration pull 2021-02-08
v2
Dropped vmstate: Fix memory leak in vmstate_handle_alloc
Broke on Power
Added migration: only check page size match if RAM postcopy is enabled
# gpg: Signature made Mon 08 Feb 2021 11:28:14 GMT
# gpg: using RSA key 45F5C71B4A0CB7FB977A9FA90516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>" [full]
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A 9FA9 0516 331E BC5B FDE7
* remotes/dgilbert/tags/pull-migration-20210208a: (27 commits)
migration: only check page size match if RAM postcopy is enabled
migration: introduce snapshot-{save, load, delete} QMP commands
iotests: fix loading of common.config from tests/ subdir
iotests: add support for capturing and matching QMP events
migration: introduce a delete_snapshot wrapper
migration: wire up support for snapshot device selection
migration: control whether snapshots are ovewritten
block: rename and alter bdrv_all_find_snapshot semantics
block: allow specifying name of block device for vmstate storage
block: add ability to specify list of blockdevs during snapshot
migration: stop returning errno from load_snapshot()
migration: Make save_snapshot() return bool, not 0/-1
block: push error reporting into bdrv_all_*_snapshot functions
migration: Display the migration blockers
migration: Add blocker information
migration: Fix a few absurdly defective error messages
migration: Fix cache_init()'s "Failed to allocate" error messages
migration: Clean up signed vs. unsigned XBZRLE cache-size
migration: Fix migrate-set-parameters argument validation
migration: introduce 'userfaultfd-wrlat.py' script
...
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'scripts')
-rwxr-xr-x | scripts/userfaultfd-wrlat.py | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/scripts/userfaultfd-wrlat.py b/scripts/userfaultfd-wrlat.py new file mode 100755 index 0000000..0684be4 --- /dev/null +++ b/scripts/userfaultfd-wrlat.py @@ -0,0 +1,122 @@ +#!/usr/bin/python3 +# +# userfaultfd-wrlat Summarize userfaultfd write fault latencies. +# Events are continuously accumulated for the +# run, while latency distribution histogram is +# dumped each 'interval' seconds. +# +# For Linux, uses BCC, eBPF. +# +# USAGE: userfaultfd-lat [interval [count]] +# +# Copyright Virtuozzo GmbH, 2020 +# +# Authors: +# Andrey Gruzdev <andrey.gruzdev@virtuozzo.com> +# +# This work is licensed under the terms of the GNU GPL, version 2 or +# later. See the COPYING file in the top-level directory. + +from __future__ import print_function +from bcc import BPF +from ctypes import c_ushort, c_int, c_ulonglong +from time import sleep +from sys import argv + +def usage(): + print("USAGE: %s [interval [count]]" % argv[0]) + exit() + +# define BPF program +bpf_text = """ +#include <uapi/linux/ptrace.h> +#include <linux/mm.h> + +BPF_HASH(ev_start, u32, u64); +BPF_HISTOGRAM(ev_delta_hist, u64); + +/* Trace UFFD page fault start event. */ +static void do_event_start() +{ + /* Using "(u32)" to drop group ID which is upper 32 bits */ + u32 tid = (u32) bpf_get_current_pid_tgid(); + u64 ts = bpf_ktime_get_ns(); + + ev_start.update(&tid, &ts); +} + +/* Trace UFFD page fault end event. */ +static void do_event_end() +{ + /* Using "(u32)" to drop group ID which is upper 32 bits */ + u32 tid = (u32) bpf_get_current_pid_tgid(); + u64 ts = bpf_ktime_get_ns(); + u64 *tsp; + + tsp = ev_start.lookup(&tid); + if (tsp) { + u64 delta = ts - (*tsp); + /* Transform time delta to milliseconds */ + ev_delta_hist.increment(bpf_log2l(delta / 1000000)); + ev_start.delete(&tid); + } +} + +/* KPROBE for handle_userfault(). */ +int probe_handle_userfault(struct pt_regs *ctx, struct vm_fault *vmf, + unsigned long reason) +{ + /* Trace only UFFD write faults. */ + if (reason & VM_UFFD_WP) { + do_event_start(); + } + return 0; +} + +/* KRETPROBE for handle_userfault(). */ +int retprobe_handle_userfault(struct pt_regs *ctx) +{ + do_event_end(); + return 0; +} +""" + +# arguments +interval = 10 +count = -1 +if len(argv) > 1: + try: + interval = int(argv[1]) + if interval == 0: + raise + if len(argv) > 2: + count = int(argv[2]) + except: # also catches -h, --help + usage() + +# load BPF program +b = BPF(text=bpf_text) +# attach KRPOBEs +b.attach_kprobe(event="handle_userfault", fn_name="probe_handle_userfault") +b.attach_kretprobe(event="handle_userfault", fn_name="retprobe_handle_userfault") + +# header +print("Tracing UFFD-WP write fault latency... Hit Ctrl-C to end.") + +# output +loop = 0 +do_exit = 0 +while (1): + if count > 0: + loop += 1 + if loop > count: + exit() + try: + sleep(interval) + except KeyboardInterrupt: + pass; do_exit = 1 + + print() + b["ev_delta_hist"].print_log2_hist("msecs") + if do_exit: + exit() |