freebsd-skq/share/examples/hwpmc/overhead.c
mmacy 810fccd58a hwpmc: add summary command and further metadata extensions
metadata changes:
- log pmc sample rate with pmcallocate
- log proc flags with thread / process logging
  to identify user vs kernel threads

fixes:
- use log cpuid to translate event id to event name

Implement rudimentary summary command to track sample
counts by thread and process name within a pmc log.

% make -j4 buildkernel >& /dev/null &
% sudo pmcstat -S unhalted_core_cycles -S llc-misses -O foo sleep 15
% pmc summary foo
cpu_clk_unhalted.thread_p_any:
        idle: 138108207162
        clang-6.0: 105336158004
        sh: 72340108510
        make: 8642012963
        kernel: 7754011631
longest_lat_cache.miss:
        clang-6.0: 87502625
        sh: 40901227
        make: 5500165
        kernel: 3300099
        awk: 2000060

%  pmc summary -f ~/foo
idx: 278 name: cpu_clk_unhalted.thread_p_any rate: 2000003
idle: 69054
clang-6.0: 52668
sh: 36170
make: 4321
kernel: 3877
hwpmc: proc(7445): 3319
awk: 1289
xargs: 357
rand_harvestq: 181
mtree: 102
intr: 53
zfskern: 31
usb: 7
pagedaemon: 4
ntpd: 3
syslogd: 1
acpi_thermal: 1
logger: 1
syncer: 1
snmptrapd: 1
sleep: 1
idx: 17 name: longest_lat_cache.miss rate: 100003
clang-6.0: 875
sh: 409
make: 55
kernel: 33
awk: 20
hwpmc: proc(7445): 14
xargs: 9
idle: 8
intr: 3
zfskern: 2
2018-06-06 02:48:09 +00:00

107 lines
3.4 KiB
C

/*-
* Copyright (c) 2014, Neville-Neil Consulting
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*
* Author: George V. Neville-Neil
*
*/
/*
* Calculate the time overhead of starting, stopping, and recording
* pmc counters.
*
* The only argument is a counter name, such as "instruction-retired"
* which is CPU dependent and can be found with pmmcontrol(8) using
* pmccontrol -L.
*
* The start, stop, read and write operations are timed using the
* rdtsc() macro which reads the Time Stamp Counter on the CPU.
*/
#include <stdio.h>
#include <err.h>
#include <sysexits.h>
#include <sys/types.h>
#include <machine/cpufunc.h>
#include <pmc.h>
int
main(int argc, char **argv)
{
pmc_id_t pmcid;
pmc_value_t read_value;
pmc_value_t read_clear_value;
uint64_t tsc1, write_cyc, start_cyc, read_cyc, stop_cyc;
char *counter_name;
if (argc != 2)
err(EX_USAGE, "counter-name required");
counter_name = argv[1];
if (pmc_init() != 0)
err(EX_OSERR, "hwpmc(4) not loaded, kldload or update your kernel");
if (pmc_allocate(counter_name, PMC_MODE_SC, 0, 0, &pmcid, 64*1024) < 0)
err(EX_OSERR, "failed to allocate %s as a system counter in counting mode",
counter_name);
tsc1 = rdtsc();
if (pmc_write(pmcid, 0) < 0)
err(EX_OSERR, "failed to zero counter %s", counter_name);
write_cyc = rdtsc() - tsc1;
tsc1 = rdtsc();
if (pmc_start(pmcid) < 0)
err(EX_OSERR, "failed to start counter %s", counter_name);
start_cyc = rdtsc() - tsc1;
tsc1 = rdtsc();
if (pmc_read(pmcid, &read_value) < 0)
err(EX_OSERR, "failed to read counter %s", counter_name);
read_cyc = rdtsc() - tsc1;
tsc1 = rdtsc();
if (pmc_stop(pmcid) < 0)
err(EX_OSERR, "failed to stop counter %s", counter_name);
stop_cyc = rdtsc() - tsc1;
if (pmc_rw(pmcid, 0, &read_clear_value))
err(EX_OSERR, "failed to read and zero %s", counter_name);
if (pmc_release(pmcid) < 0)
err(EX_OSERR, "failed to release %s as a system counter in counting mode",
counter_name);
printf("Counter %s, read value %ld, read/clear value %ld\n",
counter_name, read_value, read_clear_value);
printf("Cycles to start: %ld\tstop: %ld\tread: %ld\twrite: %ld\n",
start_cyc, stop_cyc, read_cyc, stop_cyc);
return(0);
}