[PATCH] drm/xe/guc: Improve robustness of GuC log dumping to dmesg
Matthew Brost
matthew.brost at intel.com
Tue Apr 30 23:44:33 UTC 2024
On Tue, Apr 30, 2024 at 04:34:36PM -0700, John.C.Harrison at Intel.com wrote:
> From: John Harrison <John.C.Harrison at Intel.com>
>
> There is a debug mechanism for dumping the GuC log as an ASCII hex
> stream via dmesg. This is extremely useful for situations where it is
> not possibe to query the log from debugfs (self tests, bugs that cause
> the driver to fail to load, system hangs, etc.). However, dumping via
> dmesg is not the most reliable. The dmesg buffer is limited in size,
> can be rate limited and a simple hex stream is hard to parse by tools.
>
> So add extra information to the dump to make it more robust and
> parsable. This includes adding start and end tags to delimit the dump,
> using longer lines to reduce the per line overhead, adding a rolling
> count to check for missing lines and interleaved concurrent dumps and
> adding other important information such as the GuC version number and
> timestamp offset.
>
> Signed-off-by: John Harrison <John.C.Harrison at Intel.com>
> ---
> drivers/gpu/drm/xe/regs/xe_guc_regs.h | 1 +
> drivers/gpu/drm/xe/xe_guc_log.c | 78 ++++++++++++++++++++++-----
> 2 files changed, 66 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/regs/xe_guc_regs.h b/drivers/gpu/drm/xe/regs/xe_guc_regs.h
> index 11682e675e0f..45fb3707fabe 100644
> --- a/drivers/gpu/drm/xe/regs/xe_guc_regs.h
> +++ b/drivers/gpu/drm/xe/regs/xe_guc_regs.h
> @@ -82,6 +82,7 @@
> #define HUC_LOADING_AGENT_GUC REG_BIT(1)
> #define GUC_WOPCM_OFFSET_VALID REG_BIT(0)
> #define GUC_MAX_IDLE_COUNT XE_REG(0xc3e4)
> +#define GUC_PMTIMESTAMP XE_REG(0xc3e8)
>
> #define GUC_SEND_INTERRUPT XE_REG(0xc4c8)
> #define GUC_SEND_TRIGGER REG_BIT(0)
> diff --git a/drivers/gpu/drm/xe/xe_guc_log.c b/drivers/gpu/drm/xe/xe_guc_log.c
> index a37ee3419428..ea269efd9c21 100644
> --- a/drivers/gpu/drm/xe/xe_guc_log.c
> +++ b/drivers/gpu/drm/xe/xe_guc_log.c
> @@ -7,10 +7,19 @@
>
> #include <drm/drm_managed.h>
>
> +#include "regs/xe_guc_regs.h"
> #include "xe_bo.h"
> #include "xe_gt.h"
> #include "xe_map.h"
> +#include "xe_mmio.h"
> #include "xe_module.h"
> +#include "xe_pm.h"
> +
> +static struct xe_guc *
> +log_to_guc(struct xe_guc_log *log)
> +{
> + return container_of(log, struct xe_guc, log);
> +}
>
> static struct xe_gt *
> log_to_gt(struct xe_guc_log *log)
> @@ -49,32 +58,75 @@ static size_t guc_log_size(void)
> CAPTURE_BUFFER_SIZE;
> }
>
> +#define BYTES_PER_WORD sizeof(u32)
> +#define WORDS_PER_DUMP 8
> +#define DUMPS_PER_LINE 4
> +#define LINES_PER_READ 4
> +#define WORDS_PER_READ (WORDS_PER_DUMP * DUMPS_PER_LINE * LINES_PER_READ)
> +
> void xe_guc_log_print(struct xe_guc_log *log, struct drm_printer *p)
> {
> + static int g_count;
> + struct xe_uc_fw_version *ver = &log_to_guc(log)->fw.versions.found[XE_UC_FW_VER_RELEASE];
> struct xe_device *xe = log_to_xe(log);
> size_t size;
> - int i, j;
> + char line_buff[DUMPS_PER_LINE * WORDS_PER_DUMP * 9 + 1];
> + int l_count = g_count++;
> + int line = 0;
> + int i, j, k;
> + u64 ktime;
> + u32 stamp;
>
> xe_assert(xe, log->bo);
>
> size = log->bo->size;
>
> -#define DW_PER_READ 128
> - xe_assert(xe, !(size % (DW_PER_READ * sizeof(u32))));
> - for (i = 0; i < size / sizeof(u32); i += DW_PER_READ) {
> - u32 read[DW_PER_READ];
> + drm_printf(p, "[Capture/%d.%d] Dumping GuC log for %ps...\n",
> + l_count, line++, __builtin_return_address(0));
> +
> + drm_printf(p, "[Capture/%d.%d] GuC version %u.%u.%u\n",
> + l_count, line++, ver->major, ver->minor, ver->patch);
> +
> + ktime = ktime_get_boottime_ns();
> + drm_printf(p, "[Capture/%d.%d] Kernel timestamp: 0x%08llX [%llu]\n",
> + l_count, line++, ktime, ktime);
>
> - xe_map_memcpy_from(xe, read, &log->bo->vmap, i * sizeof(u32),
> - DW_PER_READ * sizeof(u32));
> -#define DW_PER_PRINT 4
> - for (j = 0; j < DW_PER_READ / DW_PER_PRINT; ++j) {
> - u32 *print = read + j * DW_PER_PRINT;
> + xe_pm_runtime_get(xe);
> + stamp = xe_mmio_read32(log_to_gt(log), GUC_PMTIMESTAMP);
> + xe_pm_runtime_put(xe);
Just a quick drive by comment, fine grained PM control like this frowned
upon in Xe or maybe even not allowed. Rodrigo / Matt Auld would would be
the experts here.
Presumbly all the callers should already have a PM ref.
> + drm_printf(p, "[Capture/%d.%d] GuC timestamp: 0x%08X [%u]\n",
> + l_count, line++, stamp, stamp);
>
> - drm_printf(p, "0x%08x 0x%08x 0x%08x 0x%08x\n",
> - *(print + 0), *(print + 1),
> - *(print + 2), *(print + 3));
> + drm_printf(p, "[Capture/%d.%d] CS timestamp frequency: %u Hz\n",
> + l_count, line++, log_to_gt(log)->info.reference_clock);
> +
> + xe_assert(xe, !(size % (WORDS_PER_READ * BYTES_PER_WORD)));
> + for (i = 0; i < size / BYTES_PER_WORD; i += WORDS_PER_READ) {
> + u32 read[WORDS_PER_READ];
> +
> + xe_map_memcpy_from(xe, read, &log->bo->vmap, i * BYTES_PER_WORD,
> + WORDS_PER_READ * BYTES_PER_WORD);
> +
Also I think the above pukes without a PM ref too.
Matt
> + for (j = 0; j < WORDS_PER_READ; ) {
> + u32 done = 0;
> +
> + for (k = 0; k < DUMPS_PER_LINE; k++) {
> + line_buff[done++] = ' ';
> + done += hex_dump_to_buffer(read + j,
> + sizeof(*read) * (WORDS_PER_READ - j),
> + WORDS_PER_DUMP * BYTES_PER_WORD,
> + BYTES_PER_WORD,
> + line_buff + done,
> + sizeof(line_buff) - done,
> + false);
> + j += WORDS_PER_DUMP;
> + }
> +
> + drm_printf(p, "[Capture/%d.%d]%s\n", l_count, line++, line_buff);
> }
> }
> +
> + drm_printf(p, "[Capture/%d.%d] Done.\n", l_count, line++);
> }
>
> int xe_guc_log_init(struct xe_guc_log *log)
> --
> 2.43.2
>
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