linaro-dev May 2014

linaro-dev@lists.linaro.org

27 participants
37 discussions

by Mohammad Merajul Islam Molla

Hello Amit/Robert/Others, I was looking into the code for heat_cpu.c in pm-qa. I think there are some issues with the current implementation. Please find details below - 1. #define NR_THREAD 3 pid_t thr_id[NR_THREAD]; I think the array thr_id should be dynamically allocated as number of threads depend on number of cpus. However, we can eliminate the need for this array as mentioned below at no 7. 2. There is no error checking for sysconf (...) call (line 83). If this call fails num_cpus will be -1 which is a problem. 3. at line 122, pthread_t *p_thread_ptr = (pthread_t *) malloc( num_cpus * sizeof(pthread_attr_t)); we are allocating space for pthread_t. So sizeof(ptread_t) should be used instead of sizeof(pthread_attr_t). 4. at line 144, SCHED_NORMAL is used. On my Ubuntu 13.04, <sched.h> does not define SCHED_NORMAL. So it gives compile error if ANDROID is defined. heat_cpu.c:145:44: error: ‘SCHED_NORMAL’ undeclared (first use in this function) We can either use SCHED_OTHER (which is equivalent to SCHED_NORMAL) or include <linux/sched.h> 5. at line 168, error message is misleading. This error is related to failure from pthread_create, not during setting affinity. 6. at line 76, the call to gettid results in linking error - heat_cpu.c: In function ‘do_loop’: heat_cpu.c:77:2: warning: implicit declaration of function ‘gettid’ [-Wimplicit-function-declaration] /tmp/ccAhcUGE.o: In function `do_loop': heat_cpu.c:(.text+0x4e): undefined reference to `gettid' There is no libc wrapper for gettid. So I think it should be called as below - #include <sys/syscall.h> thr_id[thread] = syscall(SYS_gettid); With this changes the compilation warning and link error goes away and it works. However, this call can be eliminated as suggested below at no 7. 7. There is a potential race condition between line 171 & 182, despite the synchronization mechanism (mutex & condition variable) used. There is no guaranty that do_loop(...) will execute first and thr_id[thread] = gettid(); will execute before setting affinity as noted from below debug output - setting affinity for : 0 setting affinity for : 0 setting affinity for : 0 setting affinity for : 0 The code is setting affinity for tid 0, which it should not, despite the synchronization code. However, we can eliminate need for thr_id and the associated synchronization if we use pthread_setaffinity_np(...) . Would you care to test the alternative implementation using the patch below (also attached)? -------------------------------------------------------------------- diff --git a/utils/heat_cpu.c b/utils/heat_cpu.c index 90d8a97..236cb1d 100644 --- a/utils/heat_cpu.c +++ b/utils/heat_cpu.c @@ -47,23 +47,12 @@ #include <string.h> #include <math.h> -#define NR_THREAD 3 - int cont = 1; -int cpu_index; long long a = 1, c = 1; float f = M_PI; -pid_t thr_id[NR_THREAD]; int moderate_inst; - -#ifdef ANDROID -int conditionMet; -pthread_cond_t cond = PTHREAD_COND_INITIALIZER; -pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; -#endif - void *do_loop(void *data) { const long long b = 3; @@ -71,14 +60,6 @@ void *do_loop(void *data) a = 1; c = 1; -#ifdef ANDROID - long int thread = (long int) data; - thr_id[thread] = gettid(); - pthread_mutex_lock(&mutex); - while (!conditionMet) - pthread_cond_wait(&cond, &mutex); - pthread_mutex_unlock(&mutex); -#endif while (cont) { if (!moderate_inst) { @@ -96,9 +77,15 @@ void *do_loop(void *data) int main(int arg_count, char *argv[]) { int ret, i; - int num_cpus = sysconf(_SC_NPROCESSORS_ONLN); + int num_cpus; cpu_set_t cpuset; + num_cpus = sysconf(_SC_NPROCESSORS_ONLN); + if (num_cpus < 0) { + printf("ERROR: sysconf error\n"); + return -1; + } + printf("Num CPUs: %d\n", num_cpus); if (arg_count > 1) { if (!strcmp("moderate", argv[1])) { @@ -120,7 +107,7 @@ int main(int arg_count, char *argv[]) } pthread_t *p_thread_ptr = (pthread_t *) malloc( - num_cpus * sizeof(pthread_attr_t)); + num_cpus * sizeof(pthread_t)); if (!p_thread_ptr) { printf("ERROR: out of memory\n"); @@ -141,7 +128,7 @@ int main(int arg_count, char *argv[]) #endif #else - ret = pthread_attr_setschedpolicy(&p[i], SCHED_NORMAL); + ret = pthread_attr_setschedpolicy(&p[i], SCHED_OTHER); #endif /* for each new object */ CPU_SET(i, &cpuset); @@ -156,7 +143,7 @@ int main(int arg_count, char *argv[]) return ret; } #endif - CPU_CLR(i, &cpuset); + CPU_CLR(i, &cpuset); } @@ -165,29 +152,23 @@ int main(int arg_count, char *argv[]) ret = pthread_create(&p_thread_ptr[i], &p[i], do_loop, (void *)i); if (ret < 0) - printf("Error setting affinity for cpu%d\n", i); + printf("Error creating thread for cpu%d\n", i); #ifdef ANDROID CPU_ZERO(&cpuset); CPU_SET(i, &cpuset); - ret = sched_setaffinity(thr_id[i], sizeof(cpuset), &cpuset); + ret = pthread_setaffinity_np(p_thread_ptr[i], sizeof(cpuset), &cpuset); if (ret) { - printf("Error setting affinity on pthread th_id\n"); + printf("Error setting affinity on pthread\n"); printf("Error: %s\n", strerror(ret)); return ret; } #endif } -#ifdef ANDROID - pthread_mutex_lock(&mutex); - conditionMet = 1; - pthread_cond_broadcast(&cond); - pthread_mutex_unlock(&mutex); -#endif - while (1) sleep(1); + return 0; } -- Thanks, -Meraj

10 years, 7 months

[PATCH PMQA] cpuidle_killer: allocate per cpu process array dynamically

by Sanjay Singh Rawat

currently percpu process array is set to 2, which results in segfault Signed-off-by: Sanjay Singh Rawat <sanjay.rawat(a)linaro.org> --- cpuidle/cpuidle_killer.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/cpuidle/cpuidle_killer.c b/cpuidle/cpuidle_killer.c index 5e7320f..09009ef 100644 --- a/cpuidle/cpuidle_killer.c +++ b/cpuidle/cpuidle_killer.c @@ -104,7 +104,7 @@ int main(int argc, char *argv[]) { int ret, i, nrcpus = 2; int nrsleeps, delay; - pid_t pids[nrcpus]; + pid_t *pids; struct timex timex = { 0 }; if (adjtimex(&timex) < 0) { @@ -121,6 +121,11 @@ int main(int argc, char *argv[]) } fprintf(stderr, "found %d cpu(s)\n", nrcpus); + pids = (pid_t *) calloc(nrcpus, sizeof(pid_t)); + if (pids == NULL) { + fprintf(stderr, "error: calloc failed\n"); + return 1; + } for (i = 0; i < nrcpus; i++) { -- 1.7.10.4

10 years, 7 months

[PATCH[ Cross-compile support in Powerdebug Makefile

by Mohammad Merajul Islam Molla

Adding support for cross-compilation in powerdebug Makefile. diff --git a/Makefile b/Makefile index 2da9d67..d7c5394 100644 --- a/Makefile +++ b/Makefile @@ -2,7 +2,8 @@ BINDIR=/usr/sbin MANDIR=/usr/share/man/man8 CFLAGS?=-O1 -g -Wall -Wshadow -CC?=gcc +LD = $(CROSS_COMPILE)ld +CC = $(CROSS_COMPILE)gcc OBJS = powerdebug.o sensor.o clocks.o regulator.o gpio.o \ display.o tree.o utils.o mainloop.o -- -Meraj

10 years, 7 months

Powertop Bugs on ARM [1311381, 1316096]

by Mohammad Merajul Islam Molla

Hello, I tested powertop on Samsung Arndale Board with Ubuntu Saucy Server 14.01 with custom kernel (config file attached, powertop config options enabled), and reported a bug 1316096. Also, I found the other bug 1316096 happening on arndale board. In short, bug 1316096 - Powertop displays "nan" on top [summary] where it should show legal value. Summary: nan wakeups/second, nan GPU ops/seconds, nan VFS ops/sec and -0.0% CPU use <--- displays "nan" instead of valid value bug 1316096 - Idle stats & Frequency stats pages are empty. I did some debugging and it seems that the root cause of both the bugs may be same. It looks like the parsing code enumerate_cpus()[src/cpu/cpu.cpp] called from main.cpp, is expecting /proc/cpuinfo file in a particular format which works on Intel but not on ARM. On Intel, it gets the file in the format expected. However, on ARM on Arndale board with saucy server, the file looks as below - processor : 0 model name : ARMv7 Processor rev 4 (v7l) Features : swp half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x0 CPU part : 0xc0f CPU revision : 4 processor : 1 model name : ARMv7 Processor rev 4 (v7l) Features : swp half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x0 CPU part : 0xc0f CPU revision : 4 Hardware : SAMSUNG EXYNOS5 (Flattened Device Tree) Revision : 0000 Serial : 0000000000000000 The parsing code which gathers information about cpus, fails to parse this file and as a result the vector "all_cpus" remains empty. I played with it a bit more and added a few lines to get a work around as follows - in function enumarate_cpus(): if (strncmp(line, "processor\t",10) == 0) { char *c; c = strchr(line, ':'); if (c) { c++; number = strtoull(c, NULL, 10); * handle_one_cpu(number, "Samsung", 0, 0); [ line added]* * set_max_cpu(number); [ line added]* } } With this changes, idle stat and frequency pages were populated and summary was shown properly as noted below - *Summary: 392.6 wakeups/second, 0.0 GPU ops/seconds, 0.0 VFS ops/sec and 4.0% CPU use* I think due to this bug, the information shown on summary page was also not correct and some other info displayed by powertop may be incorrect too. Please comment. -- Thanks, -Meraj

10 years, 7 months

[PATCH] Powertop Bugs on ARM [1311381, 1316096]

by Mohammad Merajul Islam Molla

Patch for powertop bugs 1311281, 1316906. Details here - http://lists.linaro.org/pipermail/linaro-dev/2014-May/017142.html http://lists.linaro.org/pipermail/linaro-dev/2014-May/017143.html diff --git a/src/cpu/cpu.cpp b/src/cpu/cpu.cpp index 4a7e197..140d7ed 100644 --- a/src/cpu/cpu.cpp +++ b/src/cpu/cpu.cpp @@ -262,6 +262,8 @@ void enumerate_cpus(void) if (c) { c++; number = strtoull(c, NULL, 10); + handle_one_cpu(number, "ARMv7", 0, 0); + set_max_cpu(number); } } if (strncmp(line, "cpu family\t",11) == 0) { -- Thanks, -Meraj

10 years, 7 months

[PATCH]: PowerTOP README file needs to be updated

by Mohammad Merajul Islam Molla

Hello, It looks like README file in powertop branch is out of sync with how powertop should be actually built. It should be updated. diff --git a/README b/README index 2961eba..d83b315 100644 --- a/README +++ b/README @@ -2,9 +2,10 @@ ------------------------------ To build and install PowerTOP type the following commands, - ./configure - ./make - ./make install + autoreconf -sfi + ./configure + make + make install Note: For Android (running Intel Architecture ) there is a Android.mk that was provided by community members, and at this time is supported -- Thanks, -Meraj

10 years, 7 months

why is the the smp_mb() in arm64's barrier.h "dmb ish"?

by KelvinKLi＠via-alliance.com

Hi All, In arch/arm64/include/asm/barrier.h, there is the definition of smp_mb()/smp_rmb()/smp_wmb() for arm64. I noticed that all the 3 macors are using "dmb ishxx", which is only affect the cluster of the CPU executing the instruction. But in the big.LITTLE system, there will be 2 cluster. So the smp_mb()/smp_rmb()/smp_wmb() cannot affect all the CPU in the system. Is there other considerations so that smp_mb()/smp_rmb()/smp_wmb() are implemented to "only affecting inner sharable cores"? Best Regards, Kelvin K. Li --------------------------------------------------------------- Software Team, VIA Technologies, Inc. 5F, VIA Tower, 1 Zhongguancun East Road, Haidian District, Beijing, 100084 Tel: 86-10-59852288 ext.3620 mailto: kelvinkli(a)via-alliance.com

10 years, 7 months

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linaro-dev May 2014