Attachment 316980 Details for Bug 462622 – [POWERPC] spufs: add context switch notification log

[POWERPC] spufs: add context switch notification log

POWERPC-spufs-add-context-switch-notification-log.patch (text/plain), 8.93 KB, created by IBM Bug Proxy on 2008-09-17 15:40:54 UTC

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Creator: IBM Bug Proxy

Created: 2008-09-17 15:40:54 UTC

Size: 8.93 KB

patch

obsolete

>commit 988b711447fce75e92756675930150da6d53abc2
>Author: Christian Krafft <krafft@de.ibm.com>
>Date:   Wed Sep 17 09:39:19 2008 -0400
>
>    commit 5158e9b5218bd3799c9fa8c401ad24d7f0c0a0a1
>    Author: Christoph Hellwig <hch@lst.de>
>    Date:   Tue Apr 29 17:08:38 2008 +1000
>    
>        [POWERPC] spufs: add context switch notification log
>    
>        There are userspace instrumentation tools that need to monitor spu
>        context switches. This patch adds a new file called 'switch_log' to
>        each spufs context directory that can be used to monitor the context
>        switches.
>    
>        Context switch in/out and exit from spu_run are monitored after the
>        file was first opened and can be read from it.
>    
>        Signed-off-by: Christoph Hellwig <hch@lst.de>
>        Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
>
>diff --git a/arch/powerpc/platforms/cell/spufs/context.c b/arch/powerpc/platforms/cell/spufs/context.c
>index 0ad83ae..91f2d4d 100644
>--- a/arch/powerpc/platforms/cell/spufs/context.c
>+++ b/arch/powerpc/platforms/cell/spufs/context.c
>@@ -88,6 +88,7 @@ void destroy_spu_context(struct kref *kref)
> 		kref_put(ctx->prof_priv_kref, ctx->prof_priv_release);
> 	BUG_ON(!list_empty(&ctx->rq));
> 	atomic_dec(&nr_spu_contexts);
>+	kfree(ctx->switch_log);
> 	kfree(ctx);
> }
> 
>diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
>index e173040..edfd084 100644
>--- a/arch/powerpc/platforms/cell/spufs/file.c
>+++ b/arch/powerpc/platforms/cell/spufs/file.c
>@@ -2381,6 +2381,171 @@ static const struct file_operations spufs_stat_fops = {
> 	.release	= single_release,
> };
> 
>+static inline int spufs_switch_log_used(struct spu_context *ctx)
>+{
>+	return (ctx->switch_log->head - ctx->switch_log->tail) %
>+		SWITCH_LOG_BUFSIZE;
>+}
>+
>+static inline int spufs_switch_log_avail(struct spu_context *ctx)
>+{
>+	return SWITCH_LOG_BUFSIZE - spufs_switch_log_used(ctx);
>+}
>+
>+static int spufs_switch_log_open(struct inode *inode, struct file *file)
>+{
>+	struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
>+
>+	/*
>+	 * We (ab-)use the mapping_lock here because it serves the similar
>+	 * purpose for synchronizing open/close elsewhere.  Maybe it should
>+	 * be renamed eventually.
>+	 */
>+	mutex_lock(&ctx->mapping_lock);
>+	if (ctx->switch_log) {
>+		spin_lock(&ctx->switch_log->lock);
>+		ctx->switch_log->head = 0;
>+		ctx->switch_log->tail = 0;
>+		spin_unlock(&ctx->switch_log->lock);
>+	} else {
>+		/*
>+		 * We allocate the switch log data structures on first open.
>+		 * They will never be free because we assume a context will
>+		 * be traced until it goes away.
>+		 */
>+		ctx->switch_log = kzalloc(sizeof(struct switch_log) +
>+			SWITCH_LOG_BUFSIZE * sizeof(struct switch_log_entry),
>+			GFP_KERNEL);
>+		if (!ctx->switch_log)
>+			goto out;
>+		spin_lock_init(&ctx->switch_log->lock);
>+		init_waitqueue_head(&ctx->switch_log->wait);
>+	}
>+	mutex_unlock(&ctx->mapping_lock);
>+
>+	return 0;
>+ out:
>+	mutex_unlock(&ctx->mapping_lock);
>+	return -ENOMEM;
>+}
>+
>+static int switch_log_sprint(struct spu_context *ctx, char *tbuf, int n)
>+{
>+	struct switch_log_entry *p;
>+
>+	p = ctx->switch_log->log + ctx->switch_log->tail % SWITCH_LOG_BUFSIZE;
>+
>+	return snprintf(tbuf, n, "%u.%09u %d %u %u %llu\n",
>+			(unsigned int) p->tstamp.tv_sec,
>+			(unsigned int) p->tstamp.tv_nsec,
>+			p->spu_id,
>+			(unsigned int) p->type,
>+			(unsigned int) p->val,
>+			(unsigned long long) p->timebase);
>+}
>+
>+static ssize_t spufs_switch_log_read(struct file *file, char __user *buf,
>+			     size_t len, loff_t *ppos)
>+{
>+	struct inode *inode = file->f_dentry->d_inode;
>+	struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
>+	int error = 0, cnt = 0;
>+
>+	if (!buf || len < 0)
>+		return -EINVAL;
>+
>+	while (cnt < len) {
>+		char tbuf[128];
>+		int width;
>+
>+		if (file->f_flags & O_NONBLOCK) {
>+			if (spufs_switch_log_used(ctx) <= 0)
>+				return cnt ? cnt : -EAGAIN;
>+		} else {
>+			/* Wait for data in buffer */
>+			error = wait_event_interruptible(ctx->switch_log->wait,
>+					spufs_switch_log_used(ctx) > 0);
>+			if (error)
>+				break;
>+		}
>+
>+		spin_lock(&ctx->switch_log->lock);
>+		if (ctx->switch_log->head == ctx->switch_log->tail) {
>+			/* multiple readers race? */
>+			spin_unlock(&ctx->switch_log->lock);
>+			continue;
>+		}
>+
>+		width = switch_log_sprint(ctx, tbuf, sizeof(tbuf));
>+		if (width < len) {
>+			ctx->switch_log->tail =
>+				(ctx->switch_log->tail + 1) %
>+				 SWITCH_LOG_BUFSIZE;
>+		}
>+
>+		spin_unlock(&ctx->switch_log->lock);
>+
>+		/*
>+		 * If the record is greater than space available return
>+		 * partial buffer (so far)
>+		 */
>+		if (width >= len)
>+			break;
>+
>+		error = copy_to_user(buf + cnt, tbuf, width);
>+		if (error)
>+			break;
>+		cnt += width;
>+	}
>+
>+	return cnt == 0 ? error : cnt;
>+}
>+
>+static unsigned int spufs_switch_log_poll(struct file *file, poll_table *wait)
>+{
>+	struct inode *inode = file->f_dentry->d_inode;
>+	struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
>+	unsigned int mask = 0;
>+
>+	poll_wait(file, &ctx->switch_log->wait, wait);
>+
>+	if (spufs_switch_log_used(ctx) > 0)
>+		mask |= POLLIN;
>+
>+	return mask;
>+}
>+
>+static const struct file_operations spufs_switch_log_fops = {
>+	.owner	= THIS_MODULE,
>+	.open	= spufs_switch_log_open,
>+	.read	= spufs_switch_log_read,
>+	.poll	= spufs_switch_log_poll,
>+};
>+
>+void spu_switch_log_notify(struct spu *spu, struct spu_context *ctx,
>+		u32 type, u32 val)
>+{
>+	if (!ctx->switch_log)
>+		return;
>+
>+	spin_lock(&ctx->switch_log->lock);
>+	if (spufs_switch_log_avail(ctx) > 1) {
>+		struct switch_log_entry *p;
>+
>+		p = ctx->switch_log->log + ctx->switch_log->head;
>+		ktime_get_ts(&p->tstamp);
>+		p->timebase = get_tb();
>+		p->spu_id = spu ? spu->number : -1;
>+		p->type = type;
>+		p->val = val;
>+
>+		ctx->switch_log->head =
>+			(ctx->switch_log->head + 1) % SWITCH_LOG_BUFSIZE;
>+	}
>+	spin_unlock(&ctx->switch_log->lock);
>+
>+	wake_up(&ctx->switch_log->wait);
>+}
> 
> struct tree_descr spufs_dir_contents[] = {
> 	{ "capabilities", &spufs_caps_fops, 0444, },
>@@ -2417,6 +2582,7 @@ struct tree_descr spufs_dir_contents[] = {
> 	{ "proxydma_info", &spufs_proxydma_info_fops, 0444, },
> 	{ "tid", &spufs_tid_fops, 0444, },
> 	{ "stat", &spufs_stat_fops, 0444, },
>+	{ "switch_log", &spufs_switch_log_fops, 0444 },
> 	{},
> };
> 
>diff --git a/arch/powerpc/platforms/cell/spufs/run.c b/arch/powerpc/platforms/cell/spufs/run.c
>index d30bd89..87a0e95 100644
>--- a/arch/powerpc/platforms/cell/spufs/run.c
>+++ b/arch/powerpc/platforms/cell/spufs/run.c
>@@ -413,6 +413,8 @@ long spufs_run_spu(struct spu_context *ctx, u32 *npc, u32 *event)
> 	ret = spu_run_fini(ctx, npc, &status);
> 	spu_yield(ctx);
> 
>+	spu_switch_log_notify(NULL, ctx, SWITCH_LOG_EXIT, status);
>+
> 	if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
> 	    (((status >> SPU_STOP_STATUS_SHIFT) & 0x3f00) == 0x2100))
> 		ctx->stats.libassist++;
>diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
>index 24f4c43..ee35ed1 100644
>--- a/arch/powerpc/platforms/cell/spufs/sched.c
>+++ b/arch/powerpc/platforms/cell/spufs/sched.c
>@@ -241,6 +241,7 @@ static void spu_bind_context(struct spu *spu, struct spu_context *ctx)
> 	spu->mfc_callback = spufs_mfc_callback;
> 	mb();
> 	spu_unmap_mappings(ctx);
>+	spu_switch_log_notify(spu, ctx, SWITCH_LOG_START, 0);
> 	spu_restore(&ctx->csa, spu);
> 	spu->timestamp = jiffies;
> 	spu_switch_notify(spu, ctx);
>@@ -419,6 +420,7 @@ static void spu_unbind_context(struct spu *spu, struct spu_context *ctx)
> 	spu_switch_notify(spu, NULL);
> 	spu_unmap_mappings(ctx);
> 	spu_save(&ctx->csa, spu);
>+	spu_switch_log_notify(spu, ctx, SWITCH_LOG_STOP, 0);
> 	spu->timestamp = jiffies;
> 	ctx->state = SPU_STATE_SAVED;
> 	spu->ibox_callback = NULL;
>diff --git a/arch/powerpc/platforms/cell/spufs/spufs.h b/arch/powerpc/platforms/cell/spufs/spufs.h
>index 0fd6e36..ee6932d 100644
>--- a/arch/powerpc/platforms/cell/spufs/spufs.h
>+++ b/arch/powerpc/platforms/cell/spufs/spufs.h
>@@ -47,6 +47,30 @@ enum {
> 	SPU_SCHED_SPU_RUN,	/* context is within spu_run */
> };
> 
>+enum {
>+	SWITCH_LOG_BUFSIZE = 3072,
>+};
>+
>+enum {
>+	SWITCH_LOG_START,
>+	SWITCH_LOG_STOP,
>+	SWITCH_LOG_EXIT,
>+};
>+
>+struct switch_log {
>+	spinlock_t		lock;
>+	wait_queue_head_t	wait;
>+	unsigned long		head;
>+	unsigned long		tail;
>+	struct switch_log_entry {
>+		struct timespec	tstamp;
>+		s32		spu_id;
>+		u32		type;
>+		u32		val;
>+		u64		timebase;
>+	} log[];
>+};
>+
> struct spu_context {
> 	struct spu *spu;		  /* pointer to a physical SPU */
> 	struct spu_state csa;		  /* SPU context save area. */
>@@ -117,6 +141,9 @@ struct spu_context {
> 		unsigned long long libassist;
> 	} stats;
> 
>+	/* context switch log */
>+	struct switch_log *switch_log;
>+
> 	struct list_head aff_list;
> 	int aff_head;
> 	int aff_offset;
>@@ -257,6 +284,8 @@ int spu_activate(struct spu_context *ctx, unsigned long flags);
> void spu_deactivate(struct spu_context *ctx);
> void spu_yield(struct spu_context *ctx);
> void spu_switch_notify(struct spu *spu, struct spu_context *ctx);
>+void spu_switch_log_notify(struct spu *spu, struct spu_context *ctx,
>+		u32 type, u32 val);
> void spu_set_timeslice(struct spu_context *ctx);
> void spu_update_sched_info(struct spu_context *ctx);
> void __spu_update_sched_info(struct spu_context *ctx);

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Attachments on bug 462622: 316980 | 320426 | 321075