[DTrace-devel] [PATCH 4/5] Add -xcpu support to cpc provider

[Kris Van Hees]

On Tue, Sep 05, 2023 at 12:11:41AM -0400, eugene.loh at oracle.com wrote:
> 
> Signed-off-by: Eugene Loh <eugene.loh at oracle.com>

Reviewed-by: Kris Van Hees <kris.van.hees at oracle.com>

> ---
>  libdtrace/dt_prov_cpc.c              | 17 +++++++++++------
>  test/unittest/options/tst.cpu-cpc.sh | 20 ++++++++++++++++++++
>  2 files changed, 31 insertions(+), 6 deletions(-)
>  create mode 100755 test/unittest/options/tst.cpu-cpc.sh
> 
> diff --git a/libdtrace/dt_prov_cpc.c b/libdtrace/dt_prov_cpc.c
> index fc4bb43b..9e0f5542 100644
> --- a/libdtrace/dt_prov_cpc.c
> +++ b/libdtrace/dt_prov_cpc.c
> @@ -32,6 +32,9 @@ static const dtrace_pattr_t	pattr = {
>  { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
>  };
>  
> +
> +#define FDS_CNT	(dtp->dt_options[DTRACEOPT_CPU] != DTRACEOPT_UNSET ? 1 : dtp->dt_conf.num_online_cpus)
> +
>  typedef struct cpc_probe {
>  	char	*name;
>  	int	*fds;
> @@ -54,7 +57,7 @@ static dt_probe_t *cpc_probe_insert(dtrace_hdl_t *dtp, dt_provider_t *prv,
>  				    const char *prb)
>  {
>  	cpc_probe_t	*datap;
> -	int		i, cnt = dtp->dt_conf.num_online_cpus;
> +	int		i, cnt = FDS_CNT;
>  
>  	datap = dt_zalloc(dtp, sizeof(cpc_probe_t));
>  	if (datap == NULL)
> @@ -418,8 +421,7 @@ static int attach(dtrace_hdl_t *dtp, const dt_probe_t *prp, int bpf_fd)
>  {
>  	cpc_probe_t		*datap = prp->prv_data;
>  	struct perf_event_attr	attr;
> -	int			i, nattach = 0;;
> -	int			cnt = dtp->dt_conf.num_online_cpus;
> +	int			i, nattach = 0, cnt = FDS_CNT;
>  	char			*name = datap->name;  /* same as prp->desc->prb */
>  
>  	memset(&attr, 0, sizeof(attr));
> @@ -429,9 +431,12 @@ static int attach(dtrace_hdl_t *dtp, const dt_probe_t *prp, int bpf_fd)
>  
>  	for (i = 0; i < cnt; i++) {
>  		int fd;
> +		long long cpuid = dtp->dt_options[DTRACEOPT_CPU];
> +
> +		if (cpuid == DTRACEOPT_UNSET)
> +			cpuid = dtp->dt_conf.cpus[i].cpu_id;
>  
> -		fd = perf_event_open(&attr, -1, dtp->dt_conf.cpus[i].cpu_id,
> -				     -1, 0);
> +		fd = perf_event_open(&attr, -1, cpuid, -1, 0);
>  		if (fd < 0)
>  			continue;
>  		if (ioctl(fd, PERF_EVENT_IOC_SET_BPF, bpf_fd) < 0) {
> @@ -458,7 +463,7 @@ static int probe_info(dtrace_hdl_t *dtp, const dt_probe_t *prp,
>  static void detach(dtrace_hdl_t *dtp, const dt_probe_t *prp)
>  {
>  	cpc_probe_t	*datap = prp->prv_data;
> -	int		i, cnt = dtp->dt_conf.num_online_cpus;
> +	int		i, cnt = FDS_CNT;
>  
>  	for (i = 0; i < cnt; i++) {
>  		if (datap->fds[i] != -1)
> diff --git a/test/unittest/options/tst.cpu-cpc.sh b/test/unittest/options/tst.cpu-cpc.sh
> new file mode 100755
> index 00000000..e1acaf99
> --- /dev/null
> +++ b/test/unittest/options/tst.cpu-cpc.sh
> @@ -0,0 +1,20 @@
> +#!/bin/bash
> +#
> +# Oracle Linux DTrace.
> +# Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
> +# Licensed under the Universal Permissive License v 1.0 as shown at
> +# http://oss.oracle.com/licenses/upl.
> +#
> +
> +dtrace=$1
> +
> +nerr=0
> +for cpu0 in `awk '/^processor[ 	]*: [0-9]*$/ {print $3}' /proc/cpuinfo`; do
> +	cpu=`$dtrace $dt_flags -xcpu=$cpu0 -qn 'cpc:::cpu_clock-all-100000000 { trace(cpu); exit(0); }'`
> +	echo expected cpu $cpu0 got cpu $cpu
> +	if [ $cpu != $cpu0 ]; then
> +		nerr=$(($nerr + 1))
> +	fi
> +done
> +
> +exit $nerr
> -- 
> 2.18.4
> 
>