Re: [PATCH v2 02/18] perf test: Add workload-ctl option

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Incorrect command logged in error message on partial write failure.
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commit 49160052733bc1acf9df33b623a7dd76ae191072
Author: James Clark <james.clark@linaro.org>

perf test: Add workload-ctl option

This commit adds a --workload-ctl option to 'perf test -w', which uses
control and ack FIFOs to coordinate the execution of builtin workloads.
This allows perf record to be scoped strictly to the workload's execution
time by waiting for synchronization.

> diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
> --- a/tools/perf/tests/builtin-test.c
> +++ b/tools/perf/tests/builtin-test.c
[ ... ]
> +static int perf_control_write_cmd(int fd, const char *cmd)
> +{
> +	size_t len = strlen(cmd);
> +	ssize_t ret;
> +
> +	while (len) {
> +		ret = write(fd, cmd, len);
> +		if (ret < 0) {
> +			if (errno == EINTR)
> +				continue;
> +			pr_err("Failed to write perf control command '%s': %m\n", cmd);

[Severity: Low]
If a previous loop iteration successfully wrote a portion of the bytes,
cmd is advanced (cmd += ret) at the bottom of the loop. If a subsequent
write fails, will this error message log only the truncated suffix of the
command rather than the full original string?

> +			return -1;
> +		}
> +
> +		if (!ret) {
> +			pr_err("Failed to write perf control command '%s': short write\n", cmd);

[Severity: Low]
Similarly, could this also log an incomplete command if cmd was advanced
during a prior partial write?

> +			return -1;
> +		}
> +
> +		cmd += ret;
> +		len -= ret;
> +	}
> +
> +	return 0;
> +}

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Sashiko AI review · https://sashiko.dev/#/patchset/20260602-james-cs-context-tracking-fix-v2-0-85b5ce6f55c6@linaro.org?part=2