Time measuring in C program
0
I need to measure real and virtual (CPU) time of loop execution. This loop includes multiprocessing and child processes.
I tried with CPU:
clock_t start, end;
cpu_time_used=((double)(end-start)/CLOCKS_PER_SEC); //in sec
and for real time:
struct timeval tv1, tv2;
gettimeofday(&tv1, NULL);
gettimeofday(&tv2, NULL);
printf("Total time = %f sec. n", (double)(tv2.tv_usec - tv1.tv_usec) / 1000000) + (tv2.tv_sec - tv1.tv_sec));
But the measurements are not adequate. As far as I understand the CPU time should be a bit longer in this case, but there is almost no difference between them.
c time sys measure time.h
edited Nov 24 '18 at 22:39
Jérôme Teisseire
1,0261919
asked Nov 24 '18 at 20:59
maria.antoninamaria.antonina
134
add a comment |
0
I need to measure real and virtual (CPU) time of loop execution. This loop includes multiprocessing and child processes.
I tried with CPU:
clock_t start, end;
cpu_time_used=((double)(end-start)/CLOCKS_PER_SEC); //in sec
and for real time:
struct timeval tv1, tv2;
gettimeofday(&tv1, NULL);
gettimeofday(&tv2, NULL);
printf("Total time = %f sec. n", (double)(tv2.tv_usec - tv1.tv_usec) / 1000000) + (tv2.tv_sec - tv1.tv_sec));
But the measurements are not adequate. As far as I understand the CPU time should be a bit longer in this case, but there is almost no difference between them.
c time sys measure time.h
edited Nov 24 '18 at 22:39
Jérôme Teisseire
1,0261919
asked Nov 24 '18 at 20:59
maria.antoninamaria.antonina
134
why should CPU time be anything in relation the time difference, besides less than or equal to number of cores times wall clock delta
– Antti Haapala
Nov 25 '18 at 4:25
Also, where do you initialize thestart,end?
– Antti Haapala
Nov 25 '18 at 4:25
didn't put it there but I initialize start = clock() before the loop and then end it just after (end=clock()).
– maria.antonina
Nov 25 '18 at 12:13
add a comment |
0
0
0
I need to measure real and virtual (CPU) time of loop execution. This loop includes multiprocessing and child processes.
I tried with CPU:
clock_t start, end;
cpu_time_used=((double)(end-start)/CLOCKS_PER_SEC); //in sec
and for real time:
struct timeval tv1, tv2;
gettimeofday(&tv1, NULL);
gettimeofday(&tv2, NULL);
printf("Total time = %f sec. n", (double)(tv2.tv_usec - tv1.tv_usec) / 1000000) + (tv2.tv_sec - tv1.tv_sec));
But the measurements are not adequate. As far as I understand the CPU time should be a bit longer in this case, but there is almost no difference between them.
c time sys measure time.h
edited Nov 24 '18 at 22:39
Jérôme Teisseire
1,0261919
asked Nov 24 '18 at 20:59
maria.antoninamaria.antonina
134
I need to measure real and virtual (CPU) time of loop execution. This loop includes multiprocessing and child processes.
I tried with CPU:
clock_t start, end;
cpu_time_used=((double)(end-start)/CLOCKS_PER_SEC); //in sec
and for real time:
struct timeval tv1, tv2;
gettimeofday(&tv1, NULL);
gettimeofday(&tv2, NULL);
printf("Total time = %f sec. n", (double)(tv2.tv_usec - tv1.tv_usec) / 1000000) + (tv2.tv_sec - tv1.tv_sec));
But the measurements are not adequate. As far as I understand the CPU time should be a bit longer in this case, but there is almost no difference between them.
c time sys measure time.h
c time sys measure time.h
edited Nov 24 '18 at 22:39
Jérôme Teisseire
1,0261919
asked Nov 24 '18 at 20:59
maria.antoninamaria.antonina
134
edited Nov 24 '18 at 22:39
Jérôme Teisseire
1,0261919
asked Nov 24 '18 at 20:59
maria.antoninamaria.antonina
134
edited Nov 24 '18 at 22:39
Jérôme Teisseire
1,0261919
edited Nov 24 '18 at 22:39
Jérôme Teisseire
1,0261919
edited Nov 24 '18 at 22:39
Jérôme Teisseire
1,0261919
1,0261919
asked Nov 24 '18 at 20:59
maria.antoninamaria.antonina
134
asked Nov 24 '18 at 20:59
maria.antoninamaria.antonina
134
asked Nov 24 '18 at 20:59
maria.antoninamaria.antonina
134
134
why should CPU time be anything in relation the time difference, besides less than or equal to number of cores times wall clock delta
– Antti Haapala
Nov 25 '18 at 4:25
Also, where do you initialize thestart,end?
– Antti Haapala
Nov 25 '18 at 4:25
didn't put it there but I initialize start = clock() before the loop and then end it just after (end=clock()).
– maria.antonina
Nov 25 '18 at 12:13
add a comment |
why should CPU time be anything in relation the time difference, besides less than or equal to number of cores times wall clock delta
– Antti Haapala
Nov 25 '18 at 4:25
Also, where do you initialize thestart,end?
– Antti Haapala
Nov 25 '18 at 4:25
didn't put it there but I initialize start = clock() before the loop and then end it just after (end=clock()).
– maria.antonina
Nov 25 '18 at 12:13
why should CPU time be anything in relation the time difference, besides less than or equal to number of cores times wall clock delta
– Antti Haapala
Nov 25 '18 at 4:25
why should CPU time be anything in relation the time difference, besides less than or equal to number of cores times wall clock delta
– Antti Haapala
Nov 25 '18 at 4:25
Also, where do you initialize the
start, end?– Antti Haapala
Nov 25 '18 at 4:25
Also, where do you initialize the
start, end?– Antti Haapala
Nov 25 '18 at 4:25
didn't put it there but I initialize start = clock() before the loop and then end it just after (end=clock()).
– maria.antonina
Nov 25 '18 at 12:13
didn't put it there but I initialize start = clock() before the loop and then end it just after (end=clock()).
– maria.antonina
Nov 25 '18 at 12:13
add a comment |
0
active
oldest
votes
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
draft saved
draft discarded
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53462320%2ftime-measuring-in-c-program%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
0
active
oldest
votes
0
active
oldest
votes
active
oldest
votes
active
oldest
votes
draft saved
draft discarded
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
draft saved
draft discarded
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53462320%2ftime-measuring-in-c-program%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
why should CPU time be anything in relation the time difference, besides less than or equal to number of cores times wall clock delta
– Antti Haapala
Nov 25 '18 at 4:25
Also, where do you initialize the
start,end?– Antti Haapala
Nov 25 '18 at 4:25
didn't put it there but I initialize start = clock() before the loop and then end it just after (end=clock()).
– maria.antonina
Nov 25 '18 at 12:13