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Date:   Sat, 14 Sep 2019 16:05:33 +0800
From:   Fengguang Wu <fengguang.wu@intel.com>
To:     Hui Zhu <teawaterz@linux.alibaba.com>
Cc:     linux-kernel@vger.kernel.org
Subject: Re: [PATCH for vm-scalability] usemem: Add new option -Z|--read-again
Message-ID: <20190914080533.GA12862@wfg-t540p.sh.intel.com>
References: <1568430438-31372-1-git-send-email-teawaterz@linux.alibaba.com>
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Applied, thanks Teawater!

On Sat, Sep 14, 2019 at 11:07:18AM +0800, Hui Zhu wrote:
>usemem will read memory again after access the memory with this option.
>It can help test the speed that load page from swap to memory.
>
>Signed-off-by: Hui Zhu <teawaterz@linux.alibaba.com>
>---
> usemem.c | 46 ++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 40 insertions(+), 6 deletions(-)
>
>diff --git a/usemem.c b/usemem.c
>index 264d52a..2d31946 100644
>--- a/usemem.c
>+++ b/usemem.c
>@@ -94,6 +94,7 @@ int opt_sync_rw = 0;
> int opt_sync_free = 0;
> int opt_bind_interval = 0;
> unsigned long opt_delay = 0;
>+int opt_read_again = 0;
> int nr_task;
> int nr_thread;
> int nr_cpu;
>@@ -151,6 +152,7 @@ void usage(int ok)
> 	"    -e|--delay          delay for each page in ns\n"
> 	"    -O|--anonymous      mmap with MAP_ANONYMOUS\n"
> 	"    -U|--hugetlb        allocate hugetlbfs page\n"
>+	"    -Z|--read-again     read memory again after access the memory\n"
> 	"    -h|--help           show this message\n"
> 	,		ourname);
>
>@@ -188,6 +190,7 @@ static const struct option opts[] = {
> 	{ "sync-rw"	, 0, NULL, 'y' },
> 	{ "delay"	, 1, NULL, 'e' },
> 	{ "hugetlb"	, 0, NULL, 'U' },
>+	{ "read-again"	, 0, NULL, 'Z' },
> 	{ "help"	, 0, NULL, 'h' },
> 	{ NULL		, 0, NULL, 0 }
> };
>@@ -616,7 +619,7 @@ unsigned long do_unit(unsigned long bytes, struct drand48_data *rand_data,
> 	return rw_bytes;
> }
>
>-static void output_statistics(unsigned long unit_bytes)
>+static void output_statistics(unsigned long unit_bytes, const char *intro)
> {
> 	struct timeval stop;
> 	char buf[1024];
>@@ -629,8 +632,8 @@ static void output_statistics(unsigned long unit_bytes)
> 		(stop.tv_usec - start_time.tv_usec);
> 	throughput = ((unit_bytes * 1000000ULL) >> 10) / delta_us;
> 	len = snprintf(buf, sizeof(buf),
>-			"%lu bytes / %lu usecs = %lu KB/s\n",
>-			unit_bytes, delta_us, throughput);
>+			"%s%lu bytes / %lu usecs = %lu KB/s\n",
>+			intro, unit_bytes, delta_us, throughput);
> 	fflush(stdout);
> 	write(1, buf, len);
> }
>@@ -690,7 +693,34 @@ long do_units(void)
> 	} while (bytes);
>
> 	if (!opt_write_signal_read && unit_bytes)
>-		output_statistics(unit_bytes);
>+		output_statistics(unit_bytes, "");
>+
>+	if (opt_read_again && unit_bytes) {
>+		unsigned long rw_bytes = 0;
>+
>+		gettimeofday(&start_time, NULL);
>+		for (i = 0; i < nptr; i++) {
>+			int rep;
>+
>+			for (rep = 0; rep < reps; rep++) {
>+				if (rep > 0 && !quiet) {
>+					printf(".");
>+					fflush(stdout);
>+				}
>+
>+				rw_bytes += do_rw_once(ptrs[i], lens[i], &rand_data, 1, &rep, reps);
>+
>+				if (msync_mode) {
>+					if ((msync(ptrs[i], lens[i], msync_mode)) == -1) {
>+						fprintf(stderr, "msync failed with error %s \n", strerror(errno));
>+						exit(1);
>+					}
>+				}
>+			}
>+		}
>+
>+		output_statistics(rw_bytes, "read again ");
>+	}
>
> 	if (opt_write_signal_read) {
> 		struct sigaction act;
>@@ -731,7 +761,7 @@ long do_units(void)
> 		sigsuspend(&set);
> 		gettimeofday(&start_time, NULL);
> 		unit_bytes = do_rw_once(buffer, opt_bytes, &rand_data, 1, NULL, 0);
>-		output_statistics(unit_bytes);
>+		output_statistics(unit_bytes, "");
> 	}
>
> 	if (opt_sync_free)
>@@ -879,7 +909,7 @@ int main(int argc, char *argv[])
> 	pagesize = getpagesize();
>
> 	while ((c = getopt_long(argc, argv,
>-				"aAB:f:FPp:gqowRMm:n:t:b:ds:T:Sr:u:j:e:EHDNLWyxOUh", opts, NULL)) != -1)
>+				"aAB:f:FPp:gqowRMm:n:t:b:ds:T:Sr:u:j:e:EHDNLWyxOUZh", opts, NULL)) != -1)
> 		{
> 		switch (c) {
> 		case 'a':
>@@ -1005,6 +1035,10 @@ int main(int argc, char *argv[])
> 			map_hugetlb = MAP_HUGETLB | MAP_HUGE_2MB;
> 			break;
>
>+		case 'Z':
>+			opt_read_again = 1;
>+			break;
>+
> 		default:
> 			usage(1);
> 		}
>-- 
>2.7.4
>