[LTP] [PATCH v1] syscalls/ioprio: Add functional test case
Cyril Hrubis
chrubis@suse.cz
Fri Feb 7 12:11:06 CET 2020
Hi!
> ---
>
> Notes:
> This patch was written to be aplicable after the current test
> cases from Linus Walleij on the mailing list were corrected
> and applied. (That means, putting the runtest entires in place,
> moving the syscall function to the "ioprio.h" file, etc.)
> Slight adjustment could be necessary, though.
>
> runtest/syscalls | 1 +
> testcases/kernel/syscalls/ioprio/.gitignore | 1 +
> testcases/kernel/syscalls/ioprio/Makefile | 2 +
> testcases/kernel/syscalls/ioprio/ioprio_set03.c | 187 ++++++++++++++++++++++++
> 4 files changed, 191 insertions(+)
> create mode 100644 testcases/kernel/syscalls/ioprio/ioprio_set03.c
>
> diff --git a/runtest/syscalls b/runtest/syscalls
> index 20e4ef0f5..2c205ae8e 100644
> --- a/runtest/syscalls
> +++ b/runtest/syscalls
> @@ -543,6 +543,7 @@ ioprio_get01 ioprio_get01
>
> ioprio_set01 ioprio_set01
> ioprio_set02 ioprio_set02
> +ioprio_set03 ioprio_set03
>
> iopl01 iopl01
> iopl02 iopl02
> diff --git a/testcases/kernel/syscalls/ioprio/.gitignore b/testcases/kernel/syscalls/ioprio/.gitignore
> index 890081d8c..373079bf2 100644
> --- a/testcases/kernel/syscalls/ioprio/.gitignore
> +++ b/testcases/kernel/syscalls/ioprio/.gitignore
> @@ -1,3 +1,4 @@
> ioprio_get01
> ioprio_set01
> ioprio_set02
> +ioprio_set03
> diff --git a/testcases/kernel/syscalls/ioprio/Makefile b/testcases/kernel/syscalls/ioprio/Makefile
> index 5ea7d67db..647d296ca 100644
> --- a/testcases/kernel/syscalls/ioprio/Makefile
> +++ b/testcases/kernel/syscalls/ioprio/Makefile
> @@ -4,3 +4,5 @@ top_srcdir ?= ../../../..
>
> include $(top_srcdir)/include/mk/testcases.mk
> include $(top_srcdir)/include/mk/generic_leaf_target.mk
> +
> +ioprio_set03: CFLAGS += -pthread
> diff --git a/testcases/kernel/syscalls/ioprio/ioprio_set03.c b/testcases/kernel/syscalls/ioprio/ioprio_set03.c
> new file mode 100644
> index 000000000..333723b3a
> --- /dev/null
> +++ b/testcases/kernel/syscalls/ioprio/ioprio_set03.c
> @@ -0,0 +1,187 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2019 SUSE LLC
> + * Author: Christian Amann <camann@suse.com>
> + */
> +/*
> + * Functional test to see if the I/O priority set with ioprio_set(2)
> + * has an effect when writing to files.
> + *
> + * In order to do so, this test mounts a loop device for which the
> + * I/O scheduler is set to either 'bfq' or 'cfq'. Then two write threads
> + * are started which both simultaneusly write to a file each. One thread
> + * is set to IDLE priority while the other is set to BE.
> + * If the thread with the higher I/O priority writes at least 10% more
> + * to its file, the test is successful.
> + */
> +
> +#define _GNU_SOURCE
> +
> +#include <malloc.h>
> +#include <pthread.h>
> +#include <stdlib.h>
> +#include <time.h>
> +#include <unistd.h>
> +#include <sys/types.h>
> +#include "tst_safe_pthread.h"
> +#include "tst_test.h"
> +#include "ioprio.h"
> +
> +#define MNTPOINT "MNTPOINT"
> +#define FILE1 MNTPOINT"/file1"
> +#define FILE2 MNTPOINT"/file2"
> +#define CHUNKSIZE (blksize > 8192 ? blksize : 8192) /* Bytes */
Having macros that reference variables that were not passed as
parameters is considered a bad practice.
Why can't we have global chunksize variable that would be set up in
setup based on this calculation instead?
> +#define IOTIME (2) /* Seconds */
> +
> +#define SCHED_TEMPLATE "/sys/block/%s/queue/scheduler"
> +
> +static blksize_t blksize;
> +
> +static struct thread_data {
> + int fd;
> + pthread_t thread;
> + long prio;
> + int writes;
> + char *out_buf;
> +} tdata[2];
> +
> +static void set_io_scheduler(const char *device_name)
> +{
> + int fd;
> + unsigned int i;
> + const char * const schedulers[] = {"bfq", "cfq"};
> + const char *used_scheduler = NULL;
> + char avail_schedulers[256];
> + char sched_path[256];
> +
> + sprintf(sched_path, SCHED_TEMPLATE, device_name);
This has the very same problem as we have fixed in:
commit 70766c8f6f9d164057396c8d40a2575903f97efa
Author: Cyril Hrubis <chrubis@suse.cz>
Date: Wed Jan 8 14:48:07 2020 +0100
tst_device: Scan /sys/block/* for stat file
I guess that we should change the find_stat_file() function to a more
generic one that would take a last bits of a path and return whole sysfs
path for a given device, i.e.
int tst_dev_get_sysfs(const char *dev, char *path, size_t path_len, const char *sysfile);
Then we would call it here with:
if (tst_dev_get_sysfs(tst_device->dev, sched_path, sizeof(sched_path), "queue/scheduler"))
tst_brk(TBROK, "Cannot find sysfs file for scheduller");
> + fd = SAFE_OPEN(sched_path, O_RDWR);
> +
> + SAFE_READ(0, fd, avail_schedulers, 255);
> + avail_schedulers[255] = '\0';
> +
> + /* Check if right I/O schedulers are available */
> + for (i = 0; i < ARRAY_SIZE(schedulers); ++i) {
> + if (strstr(avail_schedulers, schedulers[i]))
> + used_scheduler = schedulers[i];
> + }
> + if (!used_scheduler)
> + tst_brk(TCONF, "Needed I/O schedulers are not available");
> +
> + /* Set I/O scheduler */
> + TEST(write(fd, used_scheduler, sizeof(used_scheduler)));
> + if (TST_RET < 0)
> + tst_brk(TBROK | TTERRNO, "Could not set I/O scheduler");
> +
> + SAFE_CLOSE(fd);
> +
> + tst_res(TINFO, "Set I/O scheduler to '%s'", used_scheduler);
> + if (TST_RET < 0)
> + tst_brk(TBROK | TTERRNO, "Could not set I/O scheduler");
Shouldn't be the order of these two messages reversed? Otherwise if we
fail at close both would be printed which would be a bit confusing.
> +}
> +
> +static void *io_thread(void *arg)
> +{
> + long thread_num = (long) arg;
> + int ret;
> +
> + ret = sys_ioprio_set(IOPRIO_WHO_PROCESS, 0, tdata[thread_num].prio);
> + if (ret == -1)
> + tst_brk(TBROK || TTERRNO, "ioprio_set() failed");
> +
> + ret = sys_ioprio_get(IOPRIO_WHO_PROCESS, 0);
> + if (ret != tdata[thread_num].prio)
> + tst_brk(TBROK, "ioprio_set() set wrong priority");
> +
> + /* align to blocksize for O_DIRECT writes */
> + tdata[thread_num].out_buf = SAFE_MEMALIGN(blksize, CHUNKSIZE);
> + memset(tdata[thread_num].out_buf, 'X', CHUNKSIZE);
Shouldn't we allocate and free these buffers in setup/cleanup?
> + tdata[thread_num].writes = 0;
> + while (1) {
> + SAFE_WRITE(1, tdata[thread_num].fd,
> + tdata[thread_num].out_buf, CHUNKSIZE);
> + tdata[thread_num].writes++;
> + if (tdata[thread_num].writes % 1000 == 0)
> + SAFE_LSEEK(tdata[thread_num].fd, 0, SEEK_SET);
> + }
> +
> + return arg;
> +}
> +
> +static void verify_ioprio(void)
> +{
> + long i;
> + time_t time_started, time_spent = 0;
> +
> + pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
> +
> + for (i = 0; i < 2; i++) {
> + SAFE_PTHREAD_CREATE(&tdata[i].thread, NULL,
> + io_thread, (void *) i);
> + }
> +
> + time_started = time(NULL);
> + while (time_spent < IOTIME) {
> + time_spent = time(NULL) - time_started;
> + usleep(10000);
> + }
We shoudn't use wall clock time for time mesurement, since these may
change when ntp daemon is adjusting system time on background.
We do have nice library functions on the top of monotonic timers, see:
https://github.com/linux-test-project/ltp/wiki/Test-Writing-Guidelines#2221-measuring-elapsed-time-and-helper-functions
> + for (i = 0; i < 2; i++)
> + pthread_cancel(tdata[i].thread);
> +
> + tst_res(TINFO, "Writes done with low priority: %d", tdata[0].writes);
> + tst_res(TINFO, "Writes done with high priority: %d", tdata[1].writes);
> +
> + /* High priority output should be at least 10% more */
> + if (tdata[1].writes >= tdata[0].writes + tdata[0].writes/10.0)
> + tst_res(TPASS, "High priority write was successful");
> + else
> + tst_res(TFAIL, "High priority write did not show any effect");
> +
> + for (i = 0; i < 2; ++i) {
> + if (tdata[i].out_buf)
> + free(tdata[i].out_buf);
> + }
> +}
> +
> +static void setup(void)
> +{
> + const char *device_name;
> + struct stat statbuf;
> +
> + device_name = &tst_device->dev[5]; /* skip '/dev/' prefix */
> +
> + set_io_scheduler(device_name);
> +
> + tdata[0].fd = SAFE_OPEN(FILE1, O_RDWR | O_CREAT | O_DIRECT, 0644);
> + tdata[1].fd = SAFE_OPEN(FILE2, O_RDWR | O_CREAT | O_DIRECT, 0644);
> +
> + tdata[0].prio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0);
> + tdata[1].prio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 0);
> +
> + SAFE_FSTAT(tdata[0].fd, &statbuf);
> + blksize = statbuf.st_blksize;
> +
> + tst_res(TINFO, "Blocksize: %ld", blksize);
> +}
> +
> +static void cleanup(void)
> +{
> + if (tdata[1].fd > 0)
> + SAFE_CLOSE(tdata[1].fd);
> + if (tdata[0].fd > 0)
> + SAFE_CLOSE(tdata[0].fd);
I guess that we should restore the original i/o scheduller here as well.
We do parse the scheduller string so we may as well save the current one
in setup.
> +}
> +
> +static struct tst_test test = {
> + .test_all = verify_ioprio,
> + .setup = setup,
> + .cleanup = cleanup,
> + .needs_root = 1,
> + .mount_device = 1,
> + .mntpoint = MNTPOINT,
> + .dev_min_size = 64,
We don't have to set this one, LTP will never work with less than 256MB
device, the dev_min_size is intended for cases when the test needs more
than that.
> + .dev_fs_type = "ext4",
> +};
> --
> 2.16.4
>
>
> --
> Mailing list info: https://lists.linux.it/listinfo/ltp
--
Cyril Hrubis
chrubis@suse.cz
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