scftorture: Count single_rpc offline failures in statistics outputgrafted

scf_torture_stats_print() aggregates each invoker thread's counters
into a local scf_statistics structure before printing, but the
n_single_rpc_ofl field is missing from the aggregation loop.  As a
result, the "single_rpc_ofl" value printed in the statistics line is
always zero, even when smp_call_function_single() invocations for the
RPC test have failed due to offline CPUs and been counted by the
invoker threads.

Add the missing accumulation so that the printed value reflects the
actual counts.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

1 files changed, 149 insertions, 0 deletions

diff --git a/tools/perf/util/zstd.c b/tools/perf/util/zstd.c
new file mode 100644
index 000000000..21a0eb585
--- /dev/null
+++ b/tools/perf/util/zstd.c
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <string.h>
+#include <linux/perf_event.h>
+
+#include "util/compress.h"
+#include "util/debug.h"
+
+int zstd_init(struct zstd_data *data, int level)
+{
+	data->comp_level = level;
+	data->dstream = NULL;
+	data->cstream = NULL;
+	return 0;
+}
+
+int zstd_fini(struct zstd_data *data)
+{
+	if (data->dstream) {
+		ZSTD_freeDStream(data->dstream);
+		data->dstream = NULL;
+	}
+
+	if (data->cstream) {
+		ZSTD_freeCStream(data->cstream);
+		data->cstream = NULL;
+	}
+
+	return 0;
+}
+
+ssize_t zstd_compress_stream_to_records(struct zstd_data *data, void *dst, size_t dst_size,
+				       void *src, size_t src_size, size_t max_record_size,
+				       size_t process_header(void *record, size_t increment))
+{
+	size_t ret, size, compressed = 0;
+	ZSTD_inBuffer input = { src, src_size, 0 };
+	ZSTD_outBuffer output;
+	void *record;
+
+	if (!data->cstream) {
+		data->cstream = ZSTD_createCStream();
+		if (data->cstream == NULL) {
+			pr_err("Couldn't create compression stream.\n");
+			return -1;
+		}
+
+		ret = ZSTD_initCStream(data->cstream, data->comp_level);
+		if (ZSTD_isError(ret)) {
+			pr_err("Failed to initialize compression stream: %s\n",
+				ZSTD_getErrorName(ret));
+			return -1;
+		}
+	}
+
+	while (input.pos < input.size) {
+		record = dst;
+		/* process_header writes the event header into record */
+		if (dst_size < sizeof(struct perf_event_header))
+			goto reset;
+		size = process_header(record, 0);
+		/* Output buffer full — cannot fit even the record header */
+		if (size > dst_size)
+			goto reset;
+		compressed += size;
+		dst += size;
+		dst_size -= size;
+		output = (ZSTD_outBuffer){ dst, (dst_size > max_record_size) ?
+						max_record_size : dst_size, 0 };
+		ret = ZSTD_compressStream(data->cstream, &output, &input);
+		ZSTD_flushStream(data->cstream, &output);
+		if (ZSTD_isError(ret)) {
+			pr_err("failed to compress %ld bytes: %s\n",
+				(long)src_size, ZSTD_getErrorName(ret));
+			goto reset;
+		}
+		size = output.pos;
+		/*
+		 * No progress: ZSTD couldn't emit any bytes into the
+		 * remaining output buffer.  Calling process_header
+		 * with size=0 would re-trigger header initialization,
+		 * double-subtracting the header size from dst_size and
+		 * underflowing the unsigned counter.
+		 */
+		if (size == 0)
+			goto reset;
+		size = process_header(record, size);
+		compressed += size;
+		dst += size;
+		dst_size -= size;
+	}
+
+	return compressed;
+
+reset:
+	/* Reset so the context is usable if the caller retries */
+	ret = ZSTD_initCStream(data->cstream, data->comp_level);
+	if (ZSTD_isError(ret))
+		pr_err("failed to reset compression context: %s\n",
+			ZSTD_getErrorName(ret));
+	return -1;
+}
+
+size_t zstd_decompress_stream(struct zstd_data *data, void *src, size_t src_size,
+			      void *dst, size_t dst_size)
+{
+	size_t ret;
+	ZSTD_inBuffer input = { src, src_size, 0 };
+	ZSTD_outBuffer output = { dst, dst_size, 0 };
+
+	if (!data->dstream) {
+		data->dstream = ZSTD_createDStream();
+		if (data->dstream == NULL) {
+			pr_err("Couldn't create decompression stream.\n");
+			return 0;
+		}
+
+		ret = ZSTD_initDStream(data->dstream);
+		if (ZSTD_isError(ret)) {
+			pr_err("Failed to initialize decompression stream: %s\n",
+				ZSTD_getErrorName(ret));
+			return 0;
+		}
+	}
+	while (input.pos < input.size) {
+		size_t prev_in = input.pos;
+		size_t prev_out = output.pos;
+
+		ret = ZSTD_decompressStream(data->dstream, &output, &input);
+		if (ZSTD_isError(ret)) {
+			pr_err("failed to decompress (B): %zd -> %zd, dst_size %zd : %s\n",
+			       src_size, output.pos, dst_size, ZSTD_getErrorName(ret));
+			return 0;
+		}
+		/*
+		 * Neither stream advanced — decompression is stuck.
+		 * Return 0 (error) rather than partial output: perf
+		 * uses ZSTD_flushStream (not ZSTD_endStream), so the
+		 * stream is continuous across compressed events.
+		 * Discarding unconsumed input would desynchronize the
+		 * decompressor, causing the next call to produce
+		 * garbage that could be misinterpreted as valid events.
+		 */
+		if (input.pos == prev_in && output.pos == prev_out)
+			return 0;
+	}
+
+	return output.pos;
+}