[ltt-dev] [PATCH 2/2] Make ltt support enable/disable each channel
Mathieu Desnoyers
mathieu.desnoyers at polymtl.ca
Tue Dec 2 12:06:48 EST 2008
* Zhaolei (zhaolei at cn.fujitsu.com) wrote:
> It can reduce system loads when user only need to trace some
> channels.
>
> Signed-off-by: Zhao Lei <zhaolei at cn.fujitsu.com>
> ---
> include/linux/ltt-tracer.h | 2 +
> ltt/ltt-serialize.c | 4 +
> ltt/ltt-tracer.c | 268 +++++++++++++++++++++++++-------------
> ltt/probes/ltt-type-serializer.c | 4 +
> 4 files changed, 190 insertions(+), 88 deletions(-)
>
> diff --git a/include/linux/ltt-tracer.h b/include/linux/ltt-tracer.h
> index a18edd1..87696a9 100644
> --- a/include/linux/ltt-tracer.h
> +++ b/include/linux/ltt-tracer.h
> @@ -711,6 +711,8 @@ int ltt_trace_set_channel_subbufsize(const char *trace_name,
> const char *channel_name, unsigned size);
> int ltt_trace_set_channel_subbufcount(const char *trace_name,
> const char *channel_name, unsigned cnt);
> +int ltt_trace_set_channel_enable(const char *trace_name,
> + const char *channel_name, unsigned enable);
> int ltt_trace_set_channel_overwrite(const char *trace_name,
> const char *channel_name, unsigned overwrite);
> int ltt_trace_alloc(const char *trace_name);
> diff --git a/ltt/ltt-serialize.c b/ltt/ltt-serialize.c
> index 3b31a30..9d7ce59 100644
> --- a/ltt/ltt-serialize.c
> +++ b/ltt/ltt-serialize.c
> @@ -633,6 +633,10 @@ notrace void ltt_vtrace(void *probe_data, void *call_data,
> rflags = 0;
> #endif
> channel = ltt_get_channel_from_index(trace, channel_index);
> + if (!channel)
> + /* channel is NULL if it is not enabled */
> + continue;
> +
> /* reserve space : header and data */
> ret = ltt_reserve_slot(trace, channel, &transport_data,
> data_size, &slot_size, &buf_offset,
> diff --git a/ltt/ltt-tracer.c b/ltt/ltt-tracer.c
> index 341074d..a14fd5f 100644
> --- a/ltt/ltt-tracer.c
> +++ b/ltt/ltt-tracer.c
> @@ -67,6 +67,69 @@ int (*ltt_statedump_functor)(struct ltt_trace_struct *trace) =
> ltt_statedump_default;
> struct module *ltt_statedump_owner;
>
> +/*
> + * Todo:
> + * Make similar function in channel.c,
> + * so it will be useful for both ltt-tracer.c and ltt-marker-control.c
> + */
> +/*
> + * Its order is MUST be same with enum ltt_channels
> + */
> +struct chan_info_struct {
> + const char *name;
> + unsigned int channel_index;
> + unsigned int def_subbufsize;
> + unsigned int def_subbufcount;
> +} chan_infos[] = {
> + [LTT_CHANNEL_CPU] = {
> + LTT_CPU_CHANNEL,
> + GET_CHANNEL_INDEX(cpu),
> + LTT_DEFAULT_SUBBUF_SIZE_HIGH,
> + LTT_DEFAULT_N_SUBBUFS_HIGH,
> + },
> + [LTT_CHANNEL_PROCESSES] = {
> + LTT_PROCESSES_CHANNEL,
> + GET_CHANNEL_INDEX(processes),
> + LTT_DEFAULT_SUBBUF_SIZE_MED,
> + LTT_DEFAULT_N_SUBBUFS_MED,
> + },
> + [LTT_CHANNEL_INTERRUPTS] = {
> + LTT_INTERRUPTS_CHANNEL,
> + GET_CHANNEL_INDEX(interrupts),
> + LTT_DEFAULT_SUBBUF_SIZE_LOW,
> + LTT_DEFAULT_N_SUBBUFS_LOW,
> + },
> + [LTT_CHANNEL_NETWORK] = {
> + LTT_NETWORK_CHANNEL,
> + GET_CHANNEL_INDEX(network),
> + LTT_DEFAULT_SUBBUF_SIZE_LOW,
> + LTT_DEFAULT_N_SUBBUFS_LOW,
> + },
> + [LTT_CHANNEL_MODULES] = {
> + LTT_MODULES_CHANNEL,
> + GET_CHANNEL_INDEX(modules),
> + LTT_DEFAULT_SUBBUF_SIZE_LOW,
> + LTT_DEFAULT_N_SUBBUFS_LOW,
> + },
> + [LTT_CHANNEL_METADATA] = {
> + LTT_METADATA_CHANNEL,
> + GET_CHANNEL_INDEX(metadata),
> + LTT_DEFAULT_SUBBUF_SIZE_LOW,
> + LTT_DEFAULT_N_SUBBUFS_LOW,
> + },
> +};
> +
> +static enum ltt_channels get_channel_type_from_name(const char *name)
> +{
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(chan_infos); i++)
> + if (!strcmp(name, chan_infos[i].name))
> + return (enum ltt_channels)i;
> +
> + return NR_LTT_CHANNELS;
> +}
> +
> /**
> * ltt_module_register : LTT module registration
> * @name : module type
> @@ -216,13 +279,17 @@ EXPORT_SYMBOL_GPL(ltt_write_trace_header);
>
> static void trace_async_wakeup(struct ltt_trace_struct *trace)
> {
> + int i;
> + struct ltt_channel_struct *chan;
> +
> /* Must check each channel for pending read wakeup */
> - trace->ops->wakeup_channel(trace->channel.metadata);
> - trace->ops->wakeup_channel(trace->channel.interrupts);
> - trace->ops->wakeup_channel(trace->channel.processes);
> - trace->ops->wakeup_channel(trace->channel.modules);
> - trace->ops->wakeup_channel(trace->channel.network);
> - trace->ops->wakeup_channel(trace->channel.cpu);
> + for (i = 0; i < NR_LTT_CHANNELS; i++) {
> + chan = *(struct ltt_channel_struct **)((char *)trace
> + + chan_infos[i].channel_index);
Hrm, this is the third place I see we have these ugly casts (it is also
in ltt_trace_alloc). Can we create a wrapper for it ? e.g. in
ltt-tracer.c :
static struct ltt_channel_struct **
ltt_get_trace_channel(struct ltt_trace_struct *trace, unsigned int idx)
{
return (struct ltt_channel_struct **)
((char *)trace + chan_infos[idx].channel_index);
}
> + /* chan is NULL if it is not traced */
> + if (chan)
> + trace->ops->wakeup_channel(chan);
> + }
> }
>
> /* Timer to send async wakeups to the readers */
> @@ -355,6 +422,14 @@ int ltt_trace_setup(const char *trace_name)
> }
>
> strncpy(new_trace->trace_name, trace_name, NAME_MAX);
> +
> + /*
> + * Datas in metadata channel(marker info) is necessary to be able to
> + * read the trace, it is enabled initially, and can't be disabled later.
> + */
> + new_trace->setting.channels[LTT_CHANNEL_METADATA].flags |=
> + CHANNEL_FLAG_ENABLE;
> +
> list_add(&new_trace->list, <t_traces.setup_head);
>
> ltt_unlock_traces();
> @@ -412,69 +487,6 @@ traces_error:
> }
> EXPORT_SYMBOL_GPL(ltt_trace_set_type);
>
> -/*
> - * Todo:
> - * Make similar function in channel.c,
> - * so it will be useful for both ltt-tracer.c and ltt-marker-control.c
> - */
> -/*
> - * Its order is MUST be same with enum ltt_channels
> - */
> -struct chan_info_struct {
> - const char *name;
> - unsigned int channel_index;
> - unsigned int def_subbufsize;
> - unsigned int def_subbufcount;
> -} chan_infos[] = {
> - [LTT_CHANNEL_CPU] = {
> - LTT_CPU_CHANNEL,
> - GET_CHANNEL_INDEX(cpu),
> - LTT_DEFAULT_SUBBUF_SIZE_HIGH,
> - LTT_DEFAULT_N_SUBBUFS_HIGH,
> - },
> - [LTT_CHANNEL_PROCESSES] = {
> - LTT_PROCESSES_CHANNEL,
> - GET_CHANNEL_INDEX(processes),
> - LTT_DEFAULT_SUBBUF_SIZE_MED,
> - LTT_DEFAULT_N_SUBBUFS_MED,
> - },
> - [LTT_CHANNEL_INTERRUPTS] = {
> - LTT_INTERRUPTS_CHANNEL,
> - GET_CHANNEL_INDEX(interrupts),
> - LTT_DEFAULT_SUBBUF_SIZE_LOW,
> - LTT_DEFAULT_N_SUBBUFS_LOW,
> - },
> - [LTT_CHANNEL_NETWORK] = {
> - LTT_NETWORK_CHANNEL,
> - GET_CHANNEL_INDEX(network),
> - LTT_DEFAULT_SUBBUF_SIZE_LOW,
> - LTT_DEFAULT_N_SUBBUFS_LOW,
> - },
> - [LTT_CHANNEL_MODULES] = {
> - LTT_MODULES_CHANNEL,
> - GET_CHANNEL_INDEX(modules),
> - LTT_DEFAULT_SUBBUF_SIZE_LOW,
> - LTT_DEFAULT_N_SUBBUFS_LOW,
> - },
> - [LTT_CHANNEL_METADATA] = {
> - LTT_METADATA_CHANNEL,
> - GET_CHANNEL_INDEX(metadata),
> - LTT_DEFAULT_SUBBUF_SIZE_LOW,
> - LTT_DEFAULT_N_SUBBUFS_LOW,
> - },
> -};
> -
> -static enum ltt_channels get_channel_type_from_name(const char *name)
> -{
> - int i;
> -
> - for (i = 0; i < ARRAY_SIZE(chan_infos); i++)
> - if (!strcmp(name, chan_infos[i].name))
> - return (enum ltt_channels)i;
> -
> - return NR_LTT_CHANNELS;
> -}
> -
> int ltt_trace_set_channel_subbufsize(const char *trace_name,
> const char *channel_name, unsigned size)
> {
> @@ -539,6 +551,52 @@ traces_error:
> }
> EXPORT_SYMBOL_GPL(ltt_trace_set_channel_subbufcount);
>
> +int ltt_trace_set_channel_enable(const char *trace_name,
> + const char *channel_name, unsigned enable)
> +{
> + int err = 0;
> + struct ltt_trace_struct *trace;
> + enum ltt_channels channel;
> +
> + ltt_lock_traces();
> +
> + trace = _ltt_trace_find_setup(trace_name);
> + if (!trace) {
> + printk(KERN_ERR "LTT : Trace not found %s\n", trace_name);
> + err = -ENOENT;
> + goto traces_error;
> + }
> +
> + channel = get_channel_type_from_name(channel_name);
> + if (channel == NR_LTT_CHANNELS) {
> + printk(KERN_ERR "LTT : Channel %s is not present.\n",
> + channel_name);
> + err = -EINVAL;
> + goto traces_error;
> + }
> +
> + /*
> + * Datas in metadata channel(marker info) is necessary to be able to
> + * read the trace, we always enable this channel.
> + */
> + if (!enable && channel == LTT_CHANNEL_METADATA) {
> + err = -EINVAL;
> + goto traces_error;
> + }
> +
> + if (enable)
> + trace->setting.channels[channel].flags |=
> + CHANNEL_FLAG_ENABLE;
> + else
> + trace->setting.channels[channel].flags &=
> + ~CHANNEL_FLAG_ENABLE;
> +
> +traces_error:
> + ltt_unlock_traces();
> + return err;
> +}
> +EXPORT_SYMBOL_GPL(ltt_trace_set_channel_enable);
> +
> int ltt_trace_set_channel_overwrite(const char *trace_name,
> const char *channel_name, unsigned overwrite)
> {
> @@ -563,6 +621,12 @@ int ltt_trace_set_channel_overwrite(const char *trace_name,
> goto traces_error;
> }
>
> + /*
> + * Always put the metadata channel in non-overwrite mode :
> + * This is a very low traffic channel and it can't afford to have its
> + * data overwritten : this data (marker info) is necessary to be
> + * able to read the trace.
> + */
> if (overwrite && channel == LTT_CHANNEL_METADATA) {
> err = -EINVAL;
> goto traces_error;
> @@ -635,14 +699,11 @@ int ltt_trace_alloc(const char *trace_name)
> * Config each channel's default buffersize/cnt, instead of
> * LTT_DEFAULT_SUBBUF_SIZE_LOW, ...
> */
> -
> - /*
> - * Always put the metadata channel in non-overwrite mode :
> - * This is a very low traffic channel and it can't afford to have its
> - * data overwritten : this data (marker info) is necessary to be
> - * able to read the trace.
> - */
> for (chan = 0; chan < NR_LTT_CHANNELS; chan++) {
> + if (!(trace->setting.channels[chan].flags
> + & CHANNEL_FLAG_ENABLE))
> + continue;
> +
> subbuf_size = trace->setting.channels[chan].subbuf_size;
> subbuf_cnt = trace->setting.channels[chan].subbuf_cnt;
> prepare_chan_size_num(&subbuf_size, &subbuf_cnt,
> @@ -724,6 +785,10 @@ static int ltt_trace_create(const char *trace_name, const char *trace_type,
> if (IS_ERR_VALUE(err))
> return err;
>
> + err = ltt_trace_set_channel_enable(trace_name, LTT_METADATA_CHANNEL, 1);
> + if (IS_ERR_VALUE(err))
> + return err;
> +
> err = ltt_trace_set_channel_overwrite(trace_name,
> LTT_METADATA_CHANNEL,
> is_channel_overwrite(LTT_CHANNEL_METADATA, mode));
> @@ -740,6 +805,11 @@ static int ltt_trace_create(const char *trace_name, const char *trace_type,
> if (IS_ERR_VALUE(err))
> return err;
>
> + err = ltt_trace_set_channel_enable(trace_name, LTT_INTERRUPTS_CHANNEL,
> + 1);
> + if (IS_ERR_VALUE(err))
> + return err;
> +
> err = ltt_trace_set_channel_overwrite(trace_name,
> LTT_INTERRUPTS_CHANNEL,
> is_channel_overwrite(LTT_CHANNEL_INTERRUPTS, mode));
> @@ -756,6 +826,11 @@ static int ltt_trace_create(const char *trace_name, const char *trace_type,
> if (IS_ERR_VALUE(err))
> return err;
>
> + err = ltt_trace_set_channel_enable(trace_name, LTT_PROCESSES_CHANNEL,
> + 1);
> + if (IS_ERR_VALUE(err))
> + return err;
> +
> err = ltt_trace_set_channel_overwrite(trace_name,
> LTT_PROCESSES_CHANNEL,
> is_channel_overwrite(LTT_CHANNEL_PROCESSES, mode));
> @@ -772,6 +847,10 @@ static int ltt_trace_create(const char *trace_name, const char *trace_type,
> if (IS_ERR_VALUE(err))
> return err;
>
> + err = ltt_trace_set_channel_enable(trace_name, LTT_MODULES_CHANNEL, 1);
> + if (IS_ERR_VALUE(err))
> + return err;
> +
> err = ltt_trace_set_channel_overwrite(trace_name,
> LTT_MODULES_CHANNEL,
> is_channel_overwrite(LTT_CHANNEL_MODULES, mode));
> @@ -788,6 +867,10 @@ static int ltt_trace_create(const char *trace_name, const char *trace_type,
> if (IS_ERR_VALUE(err))
> return err;
>
> + err = ltt_trace_set_channel_enable(trace_name, LTT_NETWORK_CHANNEL, 1);
> + if (IS_ERR_VALUE(err))
> + return err;
> +
> err = ltt_trace_set_channel_overwrite(trace_name,
> LTT_NETWORK_CHANNEL,
> is_channel_overwrite(LTT_CHANNEL_NETWORK, mode));
> @@ -804,6 +887,10 @@ static int ltt_trace_create(const char *trace_name, const char *trace_type,
> if (IS_ERR_VALUE(err))
> return err;
>
> + err = ltt_trace_set_channel_enable(trace_name, LTT_CPU_CHANNEL, 1);
> + if (IS_ERR_VALUE(err))
> + return err;
> +
> err = ltt_trace_set_channel_overwrite(trace_name,
> LTT_CPU_CHANNEL, is_channel_overwrite(LTT_CHANNEL_CPU, mode));
> if (IS_ERR_VALUE(err))
> @@ -855,12 +942,16 @@ traces_error:
> /* Sleepable part of the destroy */
> static void __ltt_trace_destroy(struct ltt_trace_struct *trace)
> {
> - trace->ops->finish_channel(trace->channel.metadata);
> - trace->ops->finish_channel(trace->channel.interrupts);
> - trace->ops->finish_channel(trace->channel.processes);
> - trace->ops->finish_channel(trace->channel.modules);
> - trace->ops->finish_channel(trace->channel.network);
> - trace->ops->finish_channel(trace->channel.cpu);
> + int i;
> + struct ltt_channel_struct *chan;
> +
> + for (i = 0; i < NR_LTT_CHANNELS; i++) {
> + chan = *(struct ltt_channel_struct **)((char *)trace
> + + chan_infos[i].channel_index);
Same here, wrapper should be used
> + /* chan is NULL if it is not traced */
> + if (chan)
> + trace->ops->finish_channel(chan);
> + }
>
> flush_scheduled_work();
>
> @@ -871,12 +962,13 @@ static void __ltt_trace_destroy(struct ltt_trace_struct *trace)
> */
> trace_async_wakeup(trace);
>
> - trace->ops->remove_channel(trace->channel.metadata);
> - trace->ops->remove_channel(trace->channel.interrupts);
> - trace->ops->remove_channel(trace->channel.processes);
> - trace->ops->remove_channel(trace->channel.modules);
> - trace->ops->remove_channel(trace->channel.network);
> - trace->ops->remove_channel(trace->channel.cpu);
> + for (i = 0; i < NR_LTT_CHANNELS; i++) {
> + chan = *(struct ltt_channel_struct **)((char *)trace
> + + chan_infos[i].channel_index);
And here.
I'll merge your two patches and create the wrapper in a following patch.
It will be in the next LTTng version. Thanks!
Mathieu
> + /* chan is NULL if it is not traced */
> + if (chan)
> + trace->ops->remove_channel(chan);
> + }
>
> kref_put(&trace->ltt_transport_kref, ltt_release_transport);
>
> diff --git a/ltt/probes/ltt-type-serializer.c b/ltt/probes/ltt-type-serializer.c
> index 1f93181..317d329 100644
> --- a/ltt/probes/ltt-type-serializer.c
> +++ b/ltt/probes/ltt-type-serializer.c
> @@ -55,6 +55,10 @@ notrace void _ltt_specialized_trace(void *probe_data,
> rflags = 0;
> #endif
> channel = ltt_get_channel_from_index(trace, channel_index);
> + if (!channel)
> + /* channel is NULL if it is not enabled */
> + continue;
> +
> /* reserve space : header and data */
> ret = ltt_reserve_slot(trace, channel, &transport_data,
> data_size, &slot_size, &buf_offset,
> --
> 1.5.5.3
>
>
--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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